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21.
Unsupervised anomaly detection within non‐numerical sequence data by average index difference,with application to masquerade detection
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Anomaly detection within non‐numerical sequence data has developed into an important topic of data mining, but comparatively little research has been done regarding anomaly detection without training data (unsupervised anomaly detection). One application found in computer security is the detection of a so‐called masquerade attack, which consists of an attacker abusing a regular account. This leaves only the session input, which is basically a string of non‐numerical commands, for analysis. Our previous approach to this problem introduced the use of the so‐called average index difference function for mapping the non‐numerical symbol data to a numerical space. In the present paper, we examine the theoretical properties of the average index difference function, present an enhanced unsupervised anomaly detection algorithm based on the average index difference function, show the parameters to be theoretically inferable, and evaluate the performance using real‐world data. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
22.
Hirosuke Matsui Naoyuki Maejima Nozomu Ishiguro Yuanyuan Tan Tomoya Uruga Oki Sekizawa Tomohiro Sakata Mizuki Tada 《Chemical record (New York, N.Y.)》2019,19(7):1380-1392
Three‐dimensional imaging using X‐ray as a probe is state‐of‐the‐art for the characterization of heterogeneous materials. In addition to simple imaging of sample morphology, imaging of elemental distribution and chemical states provides advanced maps of key structural parameters of functional materials. The combination of X‐ray absorption fine structure (XAFS) spectroscopy and three‐dimensional imaging such as computed tomography (CT) can visualize the three‐dimensional distribution of target elements, their valence states, and local structures in a non‐destructive manner. In this personal account, our recent results on the three‐dimensional XAFS imaging for Pt cathode catalysts in the membrane electrode assembly (MEA) of polymer electrolyte fuel cell (PEFC) are introduced. The distribution and chemical states of Pt cathode catalysts in MEAs remarkably change under PEFC operating conditions, and the 3D XAFS imaging revealed essential events in PEFC MEAs. 相似文献
23.
Junichi Sekiguchi Hironori Kuroda Yasuhiro Yamada Hirosuke Okada 《Tetrahedron letters》1985,26(19):2341-2342
A new macrolide named patulolide A was isolated from the culture broth of mutants. The structure and absolute configuration of it was determined. 相似文献
24.
Seio K Kurohagi S Kodama E Masaki Y Tsunoda H Ohkubo A Sekine M 《Organic & biomolecular chemistry》2012,10(5):994-1006
We have developed new artificial oligonucleotides which distinguish short RNA targets from long ones. The modification of the 5' termini of oligonucleotides by using adenosine derivatives that possess a bulky cyclohexyl phosphate moiety at their base moiety and a phosphate group at the position of their 5'-hydroxyl group maximized their short RNA selectivity. The 2'-O-methyl-RNA (5'-XC(m)A(m)A(m)C(m)C(m)U(m)A(m)C(m)U(m)) having these modifications exhibits ca. 10 °C higher T(m) in the duplexes with the complementary short RNA (3'-GUUGGAUGA-5') than with the long RNA (3'-AUUAUAUGUUGGAUGAUGGUUA-5'). The oligodeoxynucleotides having the same modification exhibited similar selectivity. Such short-RNA selective binding of terminally modified oligonucleotides can be employed to distinguish between mature microRNAs and pre-microRNAs. 相似文献
25.
Masaki Y Miyasaka R Hirai K Tsunoda H Ohkubo A Seio K Sekine M 《Chemical communications (Cambridge, England)》2012,48(58):7313-7315
We describe a method to predict the stability of a modified RNA duplex. Ten unique modified RNA duplexes showed a linear relationship between the calculated and experimentally determined duplex stabilities. 相似文献
26.
Oligodeoxynucleotide (ODN) synthesis, which avoids the formation of side products, is of great importance to biochemistry-based technology development. One side reaction of ODN synthesis is the cyanoethylation of the nucleobases. We suppressed this reaction by synthesizing ODNs using fully protected deoxynucleoside 3'-phosphoramidite building blocks, where the remaining reactive nucleobase residues were completely protected with acyl-, diacyl-, and acyl-oxyethylene-type groups. The detailed analysis of cyanoethylation at the nucleobase site showed that N3-protection of the thymine base efficiently suppressed the Michael addition of acrylonitrile. An ODN incorporating N3-cyanoethylthymine was synthesized using the phosphoramidite method, and primer extension reactions involving this ODN template were examined. As a result, the modified thymine produced has been proven to serve as a chain terminator. 相似文献
27.
Shi-Qi CaoItaru Okamoto Hirosuke TsunodaAkihiro Ohkubo Kohji SeioMitsuo Sekine 《Tetrahedron letters》2011,52(3):407-410
We synthesized the 3′-phosphoramidite building block of 4-thiopseudoisocytidine (s4ΨiC) and incorporated it into triplex-forming oligonucleotides (TFOs). The results of thermal denaturation of triplexes incorporating s4ΨiC showed that s4ΨiC could be used as a nucleoside component of TFOs to increase the thermal stability of triplexes at pH 7. 相似文献
28.
Hajime Katano Yuji Murayama Hirosuke Tatsumi Takao Hibi Tokuji Ikeda Ikuo Kameoka Toshihide Tsukatani 《Analytical sciences》2005,21(12):1529-1531
The influence of a phospholipid, dipalmitoyl phosphatidylcholine, layer at a nitrobenzenelwater interface on the transfer of tetraethylammonium ion and a polyammonium anti-fungus agent, poly[(dimethylimino)(2-oxo-1,2-ethanediyl)imino1,6-hexanediylimino (1-oxo-1,2-ethanediyl)(dimethylimino)-1,6-hexanediyl] ion, across the interface was studied by normal pulse voltammetry. When the phospholipid was adsorbed to form a monolayer at the nitrobenzenelwater interface by its addition to the organic phase, the half-wave potential in the current vs. potential curves for the transfer of tetraethylammonium ion did not change, but the limiting current was significantly decreased at certain sampling times, indicating a retarding effect of the layer on the ion-transfer. On the other hand, in the current vs. potential curves for the transfer of the polyammonium ion, no significant change in either the half-wave potential or the limiting current was observed upon adding the phospholipid, indicating that the polyammonium ion can easily permeate through the phospholipid layer. The results suggest a new application of the voltammetric technique to the study of cell membrane permeability to polyionic bioactive compounds. 相似文献
29.
The electron transfer (ET) reaction between bis(cyclopentadienyl)iron(II) ([Fe(II)(C(5)H(5))2]) in 1,2-dichloroethane (1,2-DCE) and hexacyanoferrate redox couple ([Fe(II/III)(CN)6](4-/3-)) in water (W) at the interface has been studied by using cyclic voltammetry. The voltammetric results can be explained well by a theoretical equation for the so-called IT-mechanism, in which a homogeneous ET reaction between [Fe(C(5)H(5))2] (partially distributed from 1,2-DCE) and [Fe(CN)6](3-) takes place in the W phase and the resultant [Fe(C(5)H(5))2]+ ion is responsible for current passage across the interface. The forward rate constant of the homogeneous ET reaction, [Fe(C(5)H(5))2] + [Fe(CN)6](3-) = [Fe(C(5)H(5))2]+ + [Fe(CN)6](4-) in W phase, k(f)(IT), was determined to be (2.9 +/- 2.2)x 10(10) M(-1) s(-1), which was in good agreement with k(f)(IT) = (3.2 +/- 2.0)x 10(10) M(-1) s(-1), which had been determined by using normal-pulse voltammetry. 相似文献
30.
Yasuhiro Yamada Toshio Hayashi Yuichi Fusho Hirosuke Okada 《Tetrahedron letters》1979,20(28):2603-2606
The synthesis of 6-acylpyridoxal, 6-carboxyethylpyridoxal and 6-(3′-aminopropyl)pyridoxal derivatives are described. 相似文献