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41.
A cutting plane algorithm for a clustering problem 总被引:2,自引:0,他引:2
In this paper we consider a clustering problem that arises in qualitative data analysis. This problem can be transformed to a combinatorial optimization problem, the clique partitioning problem. We have studied the latter problem from a polyhedral point of view and determined large classes of facets of the associated polytope. These theoretical results are utilized in this paper. We describe a cutting plane algorithm that is based on the simplex method and uses exact and heuristic separation routines for some of the classes of facets mentioned before. We discuss some details of the implementation of our code and present our computational results. We mention applications from, e.g., zoology, economics, and the political sciences. 相似文献
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Yoshihiko Nishimori Katsuhiko Kanaizuka Dr. Tomochika Kurita Toshiaki Nagatsu Yu Segawa Fumiyuki Toshimitsu Satoshi Muratsugu Dr. Mitsuya Utsuno Dr. Shoko Kume Dr. Masaki Murata Dr. Hiroshi Nishihara Prof. 《化学:亚洲杂志》2009,4(8):1361-1367
Electronic conductivity of molecular wires is a critical fundamental issue in molecular electronics. π‐Conjugated redox molecular wires with the superior long‐range electron‐transport ability could be constructed on a gold surface through the stepwise ligand–metal coordination method. The βd value, indicating the degree of decrease in the electron‐transfer rate constant with distance along the molecular wire between the electrode and the redox active species at the terminal of the wire, were 0.008–0.07 Å?1 and 0.002–0.004 Å?1 for molecular wires of bis(terpyridine)iron and bis(terpyridine)cobalt complex oligomers, respectively. The influences on βd by the chemical structure of molecular wires and the terminal redox units, temperature, electric field, and electrolyte concentration were clarified. The results indicate that facile sequential electron hopping between neighboring metal–complex units within the wire is responsible for the high electron‐transport ability. 相似文献
45.
Naoki KANEKO Akinori NAKAMURA Yukihiko WASHIMI Takashi KATO Takashi SAKURAI Yutaka ARAHATA Masahiko BUNDO Akinori TAKEDA Shumpei NIIDA Kengo ITO Kenji TOBA Koichi TANAKA Katsuhiko YANAGISAWA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2014,90(9):353-364
Alzheimer’s disease (AD) is the most common and devastating dementia. Simple and practical biomarkers for AD are urgently required for accurate diagnosis and to facilitate the development of disease-modifying interventions. The subjects for the study were selected on the basis of PiB amyloid imaging by PET. Forty PiB-positive (PiB+) individuals, including cognitively healthy controls (HC), and mild cognitive impairment and AD individuals, and 22 PiB-negative (PiB−) HC participated. Employing our novel highly sensitive immunoprecipitation-mass spectrometry, we measured plasma amyloid β-proteins (Aβs; Aβ1-40 and Aβ1-42) and Aβ-approximate peptides (AβAPs), which were cleaved from amyloid precursor protein (APP). Among the AβAPs, APP669-711 appeared to be a good reference for deciphering pathological change of Aβ1-42. We evaluated the performance of the ratio of APP669-711 to Aβ1-42 (APP669-711/Aβ1-42) as a biomarker. APP669-711/Aβ1-42 significantly increased in the PiB+ groups. The sensitivity and specificity to discriminate PiB+ individuals from PiB− individuals were 0.925 and 0.955, respectively. Our plasma biomarker precisely surrogates cerebral amyloid deposition. 相似文献
46.
Layered thin films composed of concanavalin A (Con A) and sugar-bearing polymers were prepared by a layer-by-layer deposition of Con A and the polymer on a solid surface. The sugar-induced disintegration was studied. Con A-polymer layered films could be successfully prepared using a maltose-bearing polymer (PV-MA), while melibiose- and glucose-bearing polymers (PV-MEA and PV-G) did not afford a layered film, due to a weak affinity of PV-MEA and PV-G to Con A. The Con A/PV-MA layered film was stable in pH 7 and 8 solutions, while in a pH 6 medium the film was slightly unstable. The Con A/PV-MA film was disintegrated upon the addition of sugars in solution owing to a preferential binding of the sugars to the binding site of Con A in the film. The disintegration rate was dependent on the type of sugar and its concentration. The Con A/PV-MA film was disintegrated rapidly upon the addition of methyl alpha-D-mannopyranoside, while the rate was slower upon the addition of the same concentration of D-mannose, D-glucose and methyl alpha-D-glucopyranoside. The present system may be useful for constructing sensitive devices that can release a drug or other functional molecules in response to sugars. 相似文献
47.
Let f : U → X be a map from a connected nilpotent space U to a connected rational space X. The evaluation subgroup G
*(U, X; f), which is a generalization of the Gottlieb group of X, is investigated. The key device for the study is an explicit Sullivan model for the connected component containing f of the function space of maps from U to X, which is derived from the general theory of such a model due to Brown and Szczarba (Trans Am Math Soc 349, 4931–4951, 1997).
In particular, we show that non Gottlieb elements are detected by analyzing a Sullivan model for the map f and by looking at non-triviality of higher order Whitehead products in the homotopy group of X. The Gottlieb triviality of a fibration in the sense of Lupton and Smith (The evaluation subgroup of a fibre inclusion, 2006)
is also discussed from the function space model point of view. Moreover, we proceed to consideration of the evaluation subgroup
of the fundamental group of a nilpotent space. In consequence, the first Gottlieb group of the total space of each S
1-bundle over the n-dimensional torus is determined explicitly in the non-rational case.
相似文献
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49.
Yukio Iida Masahiro Shibutani Katsuhiko Kobayashi Kazuhiko Ohnuma Yoichi Miyake Toru Noda 《Optical Review》2006,13(2):87-92
The double-pass method is thought to obtain the point spread function (PSF) in human eyes based on two techniques: the symmetric
double-pass method using the same pupil size and the asymmetric double-pass method using a different pupil size. The symmetric
double-pass method provides autocorrelation of the retinal PSF and, thus, the modulation transfer function. The asymmetric
double-pass method provides low-frequency partial-phase information and the partial phase-retrieval algorithm is applied to
obtain the complete-phase information, and to estimate the PSF. The partial phase-retrieval algorithm is based on the iteration
method proposed by Fineup and Kowalczyk and requires a lengthy computation. In this study, we propose a new high-speed phase-retrieval
algorithm based on the property that the real and imaginary parts of optical transfer functions (OTFs) continuously change
in value. 相似文献
50.
Tago Teruoki Tashiro Shizuka Hashimoto Yukiko Wakabayashi Katsuhiko Kishida Masahiro 《Journal of nanoparticle research》2003,5(1-2):55-60
Silica (SiO2)-coated ceria (CeO2) nanoparticles were prepared using water-in-oil microemulsion. Polyoxyethylene (15) cetylether and cyclohexane were used as a surfactant and organic solvent. SiO2-coated CeO2 nanoparticles were obtained by hydrolysis of metal alkoxide (tetraethylorthosilicate, TEOS) in the solution containing CeO2 precursor nanoparticles. The effects of CeO2 sources (Ce metal salt) and CeO2 particle-forming agents on the morphology of SiO2–CeO2 particles were investigated. Observation via transmission electron microscopy revealed that the type of particle-forming agent affected the nanoparticles' morphology and that CeO2 nanoparticles were spherically coated with SiO2 when using oxalic acid ((COOH)2) as a particle-forming agent of CeO2. Furthermore, the transmittance of the particles was high in the visible region (above 400 nm) and decreased in the ultraviolet region. 相似文献