• Title/Summary/Keyword: non-simple type

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Novel Self-Excited DC-DC Converters (새로운 자려식 DC-DC 컨버터)

  • Lee, Soung-Ju;Ahn, Tae-Young
    • Proceedings of the KIEE Conference
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    • 1999.07f
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    • pp.2505-2507
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    • 1999
  • This paper presents novel self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control methode. Therefore, these converters are suitable for the portable appliances with battery source. Theoretical analysis and experimental results for SOW class Buck-boost type self oscillation DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

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Workspace and Kinematical Characteristics of Planar Parallel Manipulator with Simple (간단한 정기구학을 갖는 평면운동용 병렬 매니플레이터의 구동영역 및 기구학적 특성)

  • 최기봉
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.3
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    • pp.97-104
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    • 2003
  • This paper proposes a new parallel manipulator fur plane motion, and then discusses on the workspace and kinematical characteristics of the manipulator. The conventional planar parallel manipulators have some disadvantages which are complex non-closed type direct kinematics, workspaces containing useless voids, and concave type border tines of workspaces. The proposed planar parallel manipulator overcomes the above disadvantages, that is, the manipulator has simple closed type direct kinematics, a void-free workspace, and a convex type borderline of a workspace. This paper shows the simulation result of the workspace as well as performances indices using a homogeneous inverse Jacobian.

Prediction of Non-Contact-Type Seal Leakage Using CFD (CFD를 사용한 터보기계 비접촉식 실의 누설량 예측)

  • Ha Tae-Woong
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.3 s.36
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    • pp.14-21
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    • 2006
  • Leakage reduction through annular type seals of turbomachinery is necessary for enhancing their efficiency and the precise prediction method of seal leakage is needed. The analysis based on Bulk-flow concept has been mainly used in predicting seal leakage. However, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved for improving the prediction of seal leakage. FLUENT 6 which is commercial CFD(Computational Fluid Dynamics) code based on FVM(Finite Volume Method) and SIMPLE algorism has been used to analyze leakage of various non-contact-type seals in this presentation. Comparing with the results of Bulk-flow model analysis and experiment, the result of CFD analysis shows good agreement with that of existing theoretical analysis for the incompressible grooved seal and compressive plain and staggered seal. The CFD analysis also shows improvement on the leakage prediction of the incompressible plain seal and compressive see-through-type labyrinth seal.

AN EXTENDED NON-ASSOCIATIVE ALGEBRA

  • Choi, Seul-Hee
    • Honam Mathematical Journal
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    • v.29 no.2
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    • pp.213-222
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    • 2007
  • A Weyl type algebra is defined in the paper (see [2],[4], [6], [7]). A Weyl type non-associative algebra $\bar{WN_{m,n,s}}$ and its restricted subalgebra $\bar{WN_{m,n,s_r}}$ are defined in the papers (see [1], [14], [16]). Several authors find all the derivations of an associative (Lie or non-associative) algebra (see [3], [1], [5], [7], [10], [16]). We find Der($\bar_{WN_{0,0,1_n}}$) of the algebra $\bar_{WN_{0,0,1_n}}$ and show that the algebras $\bar_{WN_{0,0,1_n}}$ and $\bar_{WN_{0,0,s_1}}$ are not isomorphic in this work. We show that the associator of $\bar_{WN_{0,0,1_n}}$ is zero.

Secondhand Smoke Exposure in Commercial Personal Computer Rooms (PC 방 금연구역의 간접흡연 노출)

  • Sohn, Hong-Ji;Oh, Ae-Ri;Kim, Ok-Gum;Lee, Ki-Young
    • Journal of Environmental Health Sciences
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    • v.36 no.4
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    • pp.288-293
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    • 2010
  • In this study, exposure to secondhand smoke (SHS) was evaluated in commercial personal computer (PC) rooms with different separation types of non-smoking areas. The particulate matter less than 2.5 ${\mu}m$ ($PM_{2.5}$) level was simultaneously measured by aerosol spectrometers in the non-smoking and smoking areas of these commercial PC rooms. Average $PM_{2.5}$ concentrations in non-smoking and smoking areas were $75\;{\mu}g/m^3$ and $136\;{\mu}g/m^3$, respectively. Although the $PM_{2.5}$ concentrations in non-smoking areas were significantly less than those in smoking areas (p<0.01), the levels still exceeded the US National Ambient Air Quality Standard of $35\;{\mu}g/m^3$. Average $PM_{2.5}$ concentrations in non-smoking areas were not significantly different with regard to area separation type, with $73\;{\mu}g/m^3$ in the no-wall type, $83\;{\mu}g/m^3$ in the wall-type, and $39\;{\mu}g/m^3$ in the separated-floor-type areas (p>0.1). Separation of the non-smoking area thus did not eliminate SHS exposure in commercial PC rooms, regardless of the type of area separation. This study demonstrates that simple separation of non-smoking areas in commercial PC rooms does not protect users from SHS.

A new approach for 3-D pushover based analysis of asymmetric buildings: development and initial evaluation

  • Baros, Dimitrios K.;Anagnostopoulos, Stavros A.
    • Earthquakes and Structures
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    • v.12 no.5
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    • pp.543-557
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    • 2017
  • Results of an extensive study aiming to properly extend the well known pushover analysis into 3-D problems of asymmetric buildings are presented in this paper. The proposed procedure uses simple, 3 DOF, one-story models with shear-beam type elements in order to quantify the effects of inelastic torsional response of such buildings. Correction coefficients for the response quantities at the "stiff" and "flexible" sides are calculated using results from non-linear time history analyses of the simple models. Their values are then applied to the results of a simple, plane pushover analysis of the detailed building models. Results from the application of the new method for a set of three, conventionally designed, five-story buildings with high values of uniaxial eccentricities are compared with those obtained from multiple non-linear dynamic time history analyses, as well as from similar pushover methods addressing the same problem. This initial evaluation indicates that the proposed procedure is a clear improvement over the simple (conventional) pushover method and, in most cases, more accurate and reliable than the other methods considered. The accuracy, however, of all these methods is reduced substantially when they are applied to torsionally flexible buildings. Thus, for such challenging problems, use of inelastic dynamic analyses for a set of two component earthquake motions appears to be the preferable solution.

The clinical usefulness of closed reduction of nasal bone using only a periosteal elevator with a rubber band

  • Park, Young Ji;Ryu, Woo Sang;Kwon, Gyu Hyeon;Lee, Kyung Suk
    • Archives of Craniofacial Surgery
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    • v.20 no.5
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    • pp.284-288
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    • 2019
  • Background: Closed reduction of nasal fracture with various instrument is performed to treat nasal fracture. Depending on the type of nasal fracture and the situation in which it is being operated, the surgeon will determine the surgical tool. The objective of this study was to investigate whether a periosteal elevator (PE) was a proper device to perform closed reduction for patients with simple nasal fractures. Methods: From March 2018 to December 2018, 50 cases of simple nasal bone fracture underwent closed reduction performed by a single surgeon. These patients were divided into two groups randomly: nasal bone reduction was performed using only PE (freer) and nasal bone reduction was performed using Walsham, Asch forcep, and Boies elevator (non-freer, non-PE). Results: The paranasal sinus computed tomography was performed on patients before and after operation to carry out an accurate measurement of reduction distance at the same level. According to the results, the interaction between instruments and fracture types had a significant influence on reduction distance (p = 0.021). To be specific, reduction distance was significantly (p= 0.004) increased by 2.157 mm when PE was used to treat patients with partial displacement compared to that when non-PEs were used. Conclusion: Closed reduction using PE and other elevator is generally an effective treatment for nasal fracture. In partial-displacement type of simple nasal fracture, closed reduction using PE can have considerable success in comparison with using classic instruments.

Self-Excited Buck-Boost DC-DC Converter (자려식 승강압형 DC-DC 컨버터)

  • Lee, Seong-Gil;An, Tae-Yeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.11
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    • pp.663-669
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    • 1999
  • This paper presents new self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control method. Therefore, these converters are suitable for the portable appliances with battery source. It is especially suited for low power DC-DC conversion applications where non isolation output power is usually required. The steady state characteristics of proposed self exciting Buck-boost DC-DC converter are analysis and the result shows good agreement with experimental value. Furthermore the experimental results for 50W class self oscillating Buck-boost DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

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A Non-edge Following Method for Solving Linear Programs (선형계산문제의 비정변형해법의 연구)

  • 백승규;안병훈
    • Journal of the Korean Operations Research and Management Science Society
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    • v.6 no.2
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    • pp.25-34
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    • 1981
  • In this paper, we propose a non-edge following method for linear programs. Unlike alledged poor performance of algorithms of this type, this method performs well at least with 25 randomly generated problems. This method is comparable to Rosen's gradient projection method as applied to the dual formulation. The latter is of general purpose, and no implementation rules are available for linear program applications. This paper suggests ways of finding improving dual feasible directions, and of allowing to move across the extreme faces of a higher dimension polyhedron. Rather simple computational rules are provided for projection operations needed at each iteration.

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A Set-theoretic Account of English Crossover Effects

  • Lee, Gunsoo
    • Korean Journal of English Language and Linguistics
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    • v.1 no.1
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    • pp.101-117
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    • 2001
  • In English, whether or not wh-movement creates weak crossover effects depends upon the type of wh-phrases that cross over. A bare interrogative like who shows a typical weak crossover effect whereas which N type (e.g. which girl) and partitive type (e.g. which of these girls) wh-phrases would show mere weaker and weakest crossover effects, respectively. Previous approaches to English crossover phenomena that resort to a binary notion of specificity or D-linking cannot account for the three-way contrast the three different types of wh-phrases show. To overcome this problem, I argue in this paper that specificity should be a non-binary set-theoretic notion and propose the following subset principle and optimal binding relation: Between two lexical nominal expressions A and B, A is regarded as more specific than B iff the denotation of A comes from a more narrowly defined non-singleton set than B. Between two lexical nominal expressions A and B, if A locally binds B, then the non-singleton set from which the denotation of A comes should be a subset of the set from which the denotation of B comes (i.e. B cannot be more specific than A). The smaller the subset (i.e. the wider the specificity gap between binder and binder), the more optimal the local binding relation is. A locally binds B iff A is coindexed with B, and A c-commands B, and there is no such C that does not bind A but binds B. Finally, I show that partitivity functions to carve out a smaller subset and thus make partitive wh-phrases more specific than simple which N type wh-phrases.

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