• Title/Summary/Keyword: prime number

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A TORSION GRAPH DETERMINED BY EQUIVALENCE CLASSES OF TORSION ELEMENTS AND ASSOCIATED PRIME IDEALS

  • Reza Nekooei;Zahra Pourshafiey
    • Bulletin of the Korean Mathematical Society
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    • v.61 no.3
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    • pp.797-811
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    • 2024
  • In this paper, we define the torsion graph determined by equivalence classes of torsion elements and denote it by AE(M). The vertex set of AE(M) is the set of equivalence classes {[x] | x ∈ T(M)*}, where two torsion elements x, y ∈ T(M)* are equivalent if ann(x) = ann(y). Also, two distinct classes [x] and [y] are adjacent in AE(M), provided that ann(x)ann(y)M = 0. We shall prove that for every torsion finitely generated module M over a Dedekind domain R, a vertex of AE(M) has degree two if and only if it is an associated prime of M.

The Relationship between Mechanical Properties and Damping Capacity of Thermo-mechanical Treated 316L Stainless Steel (가공열처리한 316L 스테인리스강의 기계적 성질과 감쇠능의 상호관계)

  • Kim, J.S.;Kang, C.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.30 no.6
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    • pp.271-278
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    • 2017
  • This study was carried out to investigate the relationship between the mechanical properties and damping capacity of thermo-mechanical treated 316L stainless steel. Dislocations, ${\varepsilon}$ and ${\alpha}^{\prime}$-martensites were formed by thermo-mechanical treatment, and the grain size was changed from micrometer to sub-micrometer by 5-cycled thermo-mechanical treatment. The volume fraction of dislocations, ${\varepsilon}$ and ${\alpha}^{\prime}$-martensites was increased, and grain size of austenite increased and lengthened by the with increasing cycle number of thermo-mechanical treatment. In 5-cycled specimens, the volume fraction of ${\alpha}^{\prime}$-martensite was more than 25% and the less than 5% of volume fraction of ${\varepsilon}$-martensite was attained. With increasing number of thermo-mechanical treatment, hardness, strength and damping capacity were increased, but elongation was decreased. Damping capacity was increased with increased hardness and strength, but decreased with increased elongation, and this result was the opposite tendency for general metal.

Efficient Authorization Conflict Detection Using Prime Number Graph Labeling in RDF Access Control (RDF 접근 제어에서 소수 그래프 레이블링을 사용한 효율적 권한 충돌 발견)

  • Kim, Jae-Hoon;Park, Seog
    • Journal of KIISE:Databases
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    • v.35 no.2
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    • pp.112-124
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    • 2008
  • RDF and OWL are the primary base technologies for implementing Semantic Web. Recently, many researches related with them, or applying them into the other application domains, have been introduced. However, relatively little work has been done for securing the RDF and OWL data. In this article, we briefly introduce an RDF triple based model for specifying RDF access authorization related with RDF security. Next, to efficiently find the authorization conflict by RDF inference, we introduce a method using prime number graph labeling in detail. The problem of authorization conflict by RDF inference is that although the lower concept is permitted to be accessed, it can be inaccessible due to the disapproval for the upper concept. Because by the RDF inference, the lower concept can be interpreted into the upper concept. Some experimental results show that the proposed method using the prime number graph labeling has better performance than the existing simple method for the detection of the authorization conflict.

A Prime Number Labeling Based on Tree Decomposition for Dynamic XML Data Management (동적 XML 데이터 관리를 위한 트리 분해 기반의 소수 레이블링 기법)

  • Byun, Chang-Woo
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.4
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    • pp.169-177
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    • 2011
  • As demand for efficiency in handling dynamic XML data grows, new dynamic XML labeling schemes have been researched. The key idea of the dynamic XML labeling scheme is to find ancestor-descendent-sibling relationships and to minimize memory space to store total label, response time and range of relabeling incurred by update operations. The prime number labeling scheme is a representative scheme which supports dynamic XML documents. It determines the ancestor-descendant relationships between two elements by a simple divisibility test of labels. When a new element is inserted into the XML data using this scheme, it does not change the label values of existing nodes. However, since each prime number must be used exclusively, labels can become significantly large. Therefore, in this paper, we introduce a novel technique to effectively reduce the problem of label overflow. The suggested idea is based on tree decomposition. When label overflow occurs, the full tree is divided into several sub-trees, and nodes in each sub-tree are separately labeled. Through experiments, we show the effectiveness of our scheme.

Differences in Artificial Nest Boxes Use of Tits Between Deciduous and Coniferous Forests

  • Rhim, Shin-Jae;Lee, Ju-Young
    • Journal of Korean Society of Forest Science
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    • v.94 no.5 s.162
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    • pp.338-341
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    • 2005
  • This study was conducted to describe the differences in artificial nest boxes use of tits between deciduous and coniferous forests at 2nd campus of Chung-Ang University ($37^{\circ}00^{\prime}04^{{\prime}{\prime}}N$, $127^{\circ}13^{\prime}96^{{\prime}{\prime}}E$), Ansung, Korea from January to August 2005. Tree species richness, tree species diversity index (H') and total basal areas were higher in deciduous forest than in coniferous forest. High, middle, low and understory canopy layers were more developed in deciduous forest, except the coverage of bush-ground layer. Varied tit Parus varius, marsh tit P. palustris and great tit P. major used the artificial nest boxes in this study. Number of breeding pairs of tits used artificial nest boxes, clutch size, and weight and size of eggs were higher in deciduous forest than in coniferous forest. The differences in habitat structure between study sites are very likely to have influenced how breeding birds used the available habitat. Artificial nest boxes could be used as management and conservation tool for birds, particularly in areas, where the availability of natural cavities and coverage of higher layer are limited.

A Labeling Methods for Keyword Search over Large XML Documents (대용량 XML 문서의 키워드 검색을 위한 레이블링 기법)

  • Sun, Dong-Han;Hwang, Soo-Chan
    • Journal of KIISE
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    • v.41 no.9
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    • pp.699-706
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    • 2014
  • As XML documents are getting bigger and more complex, a keyword-based search method that does not require structural information is needed to search these large XML documents. In order to use this method, not only all keywords expressed as nodes in the XML document must be labeled for indexing but also structural information should be well represented. However, the existing labeling methods either have very simple information of XML documents for index or represent the structural information which is difficult to deal with the increase of XML documents' size. As the size of XML documents is getting larger, it causes either the poor performance of keyword search or the exponential increase of space usage. In this paper, we present the Repetitive Prime Labeling Scheme (RPLS) in order to improve the problem of the existing labeling methods for keyword-based search of large XML documents. This method is based on the existing prime number labeling method and allows a parent's prime number to be used at a lower level repeatedly so that the number of prime numbers being generated can be reduced. Then, we show an experimental result of the comparison between our methods and the existing methods.

Real-Time Detection of Cache Side-Channel Attacks Using Non-Cache Hardware Events (비 캐시 하드웨어 이벤트를 이용한 캐시 부채널 공격 실시간 탐지)

  • Kim, Hodong;Hur, Junbeom
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.30 no.6
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    • pp.1255-1261
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    • 2020
  • Cache side-channel attack is a class of attacks to retrieve sensitive information from a system by exploiting shared cache resources in CPUs. As the attacks are delivered to wide range of environments from mobile systems to cloud systems recently, many detection strategies have been proposed. Since the conventional cache side-channel attacks are likely to incur tremendous number of cache events, most of the previous detection mechanisms were designed to carefully monitor mostly cache events. However, recently proposed attacks tend to incur less cache events during the attack. PRIME+ABORT attack, for example, leverages the Intel TSX instead of accessing cache to measure access time. Because of the characteristic, attack detection mechanisms based on cache events may hardly detect the attack. In this paper, we conduct an in-depth analysis of the PRIME+ABORT attack to identify the other useful hardware events for detection rather than cache events. Based on our finding, we present a novel mechanism called PRIME+ABORT Detector to detect the PRIME+ABORT attack and demonstrate that the detection mechanism can achieve 99.5% success rates with 0.3% performance overhead.

ON THE IDEAL CLASS GROUPS OF ℤp-EXTENSIONS OVER REAL ABELIAN FIELDS

  • Kim, Jae Moon;Ryu, Ja Do
    • Korean Journal of Mathematics
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    • v.7 no.2
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    • pp.227-233
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    • 1999
  • Let $k$ be a real abelian field and $k_{\infty}={\bigcup}_{n{\geq}0}k_n$ be its $\mathbb{Z}_p$-extension for an odd prime $p$. For each $n{\geq}0$, we denote the class number of $k_n$ by $h_n$. The following is a well known theorem: Theorem. Suppose $p$ remains inert in $k$ and the prime ideal of $k$ above $p$ totally ramifies in $k_{\infty}$. Then $p{\nmid}h_0$ if and only if $p{\nmid}h_n$ for all $n{\geq}0$. The aim of this paper is to generalize above theorem: Theorem 1. Suppose $H^1(G_n,E_n){\simeq}(\mathbb{Z}/p^n\mathbb{Z})^l$, where $l$ is the number of prime ideals of $k$ above $p$. Then $p{\nmid}h_0$ if and only if $p{\nmid}h_n$. Theorem 2. Let $k$ be a real quadratic field. Suppose that $H^1(G_1,E_1){\simeq}(\mathbb{Z}/p\mathbb{Z})^l$. Then $p{\nmid}h_0$ if and only if $p{\nmid}h_n$ for all $n{\geq}0$.

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Effect of Thermo-mechanical Treatment on the Tensile Properties of Fe-20Mn-12Cr-3Ni-3Si Damping Alloy (Fe-20Mn-12Cr-3Ni-3Si 합금의 인장성질에 미치는 가공열처리의 영향)

  • Han, H.S.;Kang, C.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.32 no.2
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    • pp.61-67
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    • 2019
  • This study was carried out to investigate the effect of thermo-mechanical treatment on the tensile properties of Fe-20Mn-12Cr-3Ni-3Si alloy with deformation induced martensite transformation. ${\alpha}^{\prime}$ and ${\varepsilon}$-martensite, dislocation, stacking fault were formed, and grain size was refined by thermo-mechanical treatment. With the increasing cycle number of thermo-mechanical treatment, volume fraction of ${\varepsilon}$ and ${\alpha}^{\prime}$-martensite, dislocation, stacking fault were increased, and grain size decreased. In 5-cycle number thermo-mechanical treated specimens, more than 10% of the volume fraction of ${\varepsilon}$-martensite and less than 3% of the volume fraction of ${\alpha}^{\prime}$-martensite were attained. Tensile strength was increased and elongation was decreased with the increasing cycle number of thermo-mechanical treatment. Tensile properties of thermo-mechanical treated alloy with deformation induced martensite transformation was affected to formation of martensite by thermo-mechanical treatment, but was large affected to increasing of dislocation and grain refining.

ON THE TOUCHARD POLYNOMIALS AND MULTIPLICATIVE PLANE PARTITIONS

  • Kim, JunKyo
    • East Asian mathematical journal
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    • v.37 no.1
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    • pp.9-17
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    • 2021
  • For a positive integer n, let μd(n) be the number of multiplicative d-dimensional partitions of ${\prod\limits_{i=1}^{n}}p_i$, where pi denotes the ith prime. The number of multiplicative partitions of a square free number with n prime factors is the Bell number μ1(n) = ��n. By the definition of the function μd(n), it can be seen that for all positive integers n, μ1(n) = Tn(1) = ��n, where Tn(x) is the nth Touchard (or exponential ) polynomial. We show that, for a positive n, μ2(n) = 2nTn(1/2). We also conjecture that for all m, μ3(m) ≤ 3mTm(1/3).