• Title/Summary/Keyword: Weak-k-configuration

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THE MINIMAL FREE RESOLUTION OF A STAR-CONFIGURATION IN ?n AND THE WEAK LEFSCHETZ PROPERTY

  • Ahn, Jea-Man;Shin, Yong-Su
    • Journal of the Korean Mathematical Society
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    • v.49 no.2
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    • pp.405-417
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    • 2012
  • We find the Hilbert function and the minimal free resolution of a star-configuration in $\mathbb{P}^n$. The conditions are provided under which the Hilbert function of a star-configuration in $\mathbb{P}^2$ is generic or non-generic We also prove that if $\mathbb{X}$ and $\mathbb{Y}$ are linear star-configurations in $\mathbb{P}^2$ of types t and s, respectively, with $s{\geq}t{\geq}3$, then the Artinian k-algebra $R/(I_{\mathbb{X}}+I_{\mathbb{Y})$ has the weak Lefschetz property.

AN ARTINIAN POINT-CONFIGURATION QUOTIENT AND THE STRONG LEFSCHETZ PROPERTY

  • Kim, Young Rock;Shin, Yong-Su
    • Journal of the Korean Mathematical Society
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    • v.55 no.4
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    • pp.763-783
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    • 2018
  • In this paper, we study an Artinian point-configuration quotient having the SLP. We show that an Artinian quotient of points in $\mathbb{p}^n$ has the SLP when the union of two sets of points has a specific Hilbert function. As an application, we prove that an Artinian linear star configuration quotient $R/(I_{\mathbb{X}}+I_{\mathbb{Y}})$ has the SLP if $\mathbb{X}$ and $\mathbb{Y}$ are linear starconfigurations in $\mathbb{p}^2$ of type s and t for $s{\geq}(^t_2)-1$ and $t{\geq}3$. We also show that an Artinian $\mathbb{k}$-configuration quotient $R/(I_{\mathbb{X}}+I_{\mathbb{Y}})$ has the SLP if $\mathbb{X}$ is a $\mathbb{k}$-configuration of type (1, 2) or (1, 2, 3) in $\mathbb{p}^2$, and $\mathbb{X}{\cup}\mathbb{Y}$ is a basic configuration in $\mathbb{p}^2$.

Effect of fibers and welded-wire reinforcements on the diaphragm behavior of composite deck slabs

  • Altoubat, Salah;Ousmane, Hisseine;Barakat, Samer
    • Steel and Composite Structures
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    • v.19 no.1
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    • pp.153-171
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    • 2015
  • Twelve large-scale composite deck slabs were instrumented and tested in a cantilever diaphragm configuration to assess the effect of fibers and welded wire mesh (WWM) on the in-plane shear capacity of composite deck slabs. The slabs were constructed with reentrant decking profile and reinforced with different types and dosages of secondary reinforcements: Conventional welded wire mesh (A142 and A98); synthetic macro-fibers (dosages of $3kg/m^3$ and $5.3kg/m^3$); and hooked-end steel fibers with a dosage of $15kg/m^3$. The deck orientation relative to the main beam (strong and weak) was also considered in this study. Fibers and WWM were found efficient in distributing the applied load to the whole matrix, inducing multiple cracking, thereby enhancing the strength and ductility of composite deck slabs. The test results indicate that fibers increased the slab's ultimate in-plane shear capacity by up to 29% and 50% in the strong and weak directions, respectively. WWM increased the ultimate in-plane shear capacity by up to 19% in the strong direction and 9% in the weak direction. The results suggest that discrete fibers can provide comparable diaphragm behavior as that with the conventional WWM.

AP Selection Criteria for UAV High-precision Indoor Positioning based on IEEE 802.11 RSSI Measurement (IEEE 802.11 RSSI 기반 무인비행로봇 실내측위를 위한 AP 선택 기법)

  • Hwang, Jun Gyu;Park, Joon Goo
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.12
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    • pp.1204-1208
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    • 2014
  • As required performance of UAV (Unmanned Aerial Vehicle) becomes more complex and complicated, required positioning accuracy is becoming more and more higher. GPS is a reliable world wide positioning providing system. Therefore, UAV generally acquires position information from GPS. But when GPS is not available such as too weak signal or too less GPS satellites environments, UAV needs alternative positioning system such as network positioning system. RSSI (Received Signal Strength Indicator) based positioning, which is one method of network positioning technologies, determines its position using RSSI measurements containing distance information from AP (Access Point)s. In that method, a selected AP's configuration has strong and tight relationship with its positioning errors. In this paper, for, we additionally account AP's configuration information by adopting DOP (Dilution of Precision) into AP selection procedures and provide more accurate RSSI based positioning results.

Squeezing Flow of Micropolar Nanofluid between Parallel Disks

  • Khan, Sheikh Irfanullah;Mohyud-Din, Syed Tauseef;Yang, Xiao-Jun
    • Journal of Magnetics
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    • v.21 no.3
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    • pp.476-489
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    • 2016
  • In the present study, squeezing flow of micropolar nanofluid between parallel infinite disks in the presence of magnetic field perpendicular to plane of the disks is taken into account. The constitutive equations that govern the flow configuration are converted into nonlinear ordinary differential with the help of suitable similarity transforms. HAM package BVPh2.0 has been employed to solve the nonlinear system of ordinary differential equations. Effects of different emerging parameters like micropolar parameter K, squeezed Reynolds number R, Hartmann number M, Brownian motion parameter Nb, thermophoresis parameter Nt, Lewis number Le for dimensionless velocities, temperature distribution and concentration profile are also discussed graphically. In the presence of strong and weak interaction (i.e. n = 0 and n = 0.5), numerical values of skin friction coefficient, wall stress coefficient, local Nusselt number and local Sherwood number are presented in tabulated form. To check the validity and reliability of the developed algorithm BVPh2.0 a numerical investigation is also a part of this study.

Improvement on Moment Resistance of a Concealed Timber Post Base Joint

  • Humbert, Jerome;Lee, Sang-Joon;Park, Joo-Saeng;Park, Moon-Jae
    • Journal of the Korea Furniture Society
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    • v.24 no.4
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    • pp.444-451
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    • 2013
  • In this paper, experimental results were presented on the moment resistance of a concealed timber post base joint aimed at replacing in a modern design introduced lately the wood to wood joints used in the traditional Korean timber house - Hanok. Preliminary results showed that the original configuration of the joint offers a limited moment resistance and a low ductility and energy dissipation. In an attempt to mitigate those limitations without undergoing major changes in the connector, three new configurations were proposed and investigated. Motivated by the wish to prevent the early failure in welds, a first approach consists in directly bolting the connector's upper plate to lower the stress on the weak welds. Alternatively, another approach focused on increasing the strength of these welds by extending their length to the full width of the metal wings. Finally, a third configuration investigated the effect of those two approaches combined. In conclusion, reinforcing the welds found out to be the best option among the presented ones. As a result, this connector considered to show proper ability for use in earthquake-resistant structures with suited lateral-resistant structural elements.

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Soft error correction controller for FPGA configuration memory (FPGA 재구성 메모리의 소프트에러 정정을 위한 제어기의 설계)

  • Baek, Jongchul;Kim, Hyungshin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5465-5470
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    • 2012
  • FPGA(Field Programmable Gate Array) devices are widely used due to their merits in circuit development time, and development cost. Among various FPGA technologies, SRAM-based FPGAs have large cell capacity so that they are attractive for complex circuit design and their reconfigurability. However, they are weak in space environment where radiation energy particles cause Single Event Upset(SEU). In this paper, we designed a controller supervising SRAM-based FPGA to protect configuration memory inside. The controller is implemented on an Anti-Fusing FPGA. Radiation test was performed on the implemented computer board and the result show that our controller provides better SEU-resilience than TMR-only system.

Salternamide E from a Saltern-derived Marine Actinomycete Streptomyces sp.

  • Kim, Seong-Hwan;Shin, Yoonho;Lee, Sang Kook;Shin, Jongheon;Oh, Dong-Chan
    • Natural Product Sciences
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    • v.21 no.4
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    • pp.273-277
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    • 2015
  • Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.

Observation of the Electromagnetically Induced Transparency and Dispersion-like Structure in Trapped Cs Atoms

  • Kim, Kyoung-Dae;Kwon, Mi-Rang;Kim, Jung-Bog;Moon, Han-Seb
    • Journal of the Optical Society of Korea
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    • v.5 no.4
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    • pp.131-135
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    • 2001
  • We report experiemtnal results demonstrating the electromagnetically induced transparency (EIT) in trapped Cs atoms. EIT occurs at the Λ-type configuration where the re0-pumping laser simultaneously plays a role as the coupling laser in the presence of a magneto-optical trapping and weak magnetic fields. Dependences of EIT signal on both the intensity and the detuning of the coupling laser were investigated. Linear absorption spectra for cold cesium atoms in the magneto-optical trap have been observed and shown the pronounced dispersion-like structure with sub-natural linewidth of 1 MHz due to the cooling laser.