A redundancy-based measure of dissimilarity among probability distributions for hierarchical clustering criteria

We introduce novel dissimilarity into a probabilistic clustering task to properly measure dissimilarity among multiple clusters when each cluster is characterized by a subpopulation in the mixture model. This measure of dissimilarity is called redundancy-based dissimilarity among probability distributions. From aspects of both source coding and a statistical hypothesis test, we shed light on several of the theoretical reasons for the redundancy-based dissimilarity among probability distributions being a reasonable measure of dissimilarity among clusters. We also elucidate a principle in common for the measures of redundancy-based dissimilarity and Ward's method in terms of hierarchical clustering criteria. Moreover, we show several related theorems that are significant for clustering tasks. In the experiments, properties of the measure of redundancy-based dissimilarity are examined in comparison with several other measures.     

Country domain governance: an analysis by data-mining of country domains

Along with protocols, domain names are critical internet resources. To build a safe, secure, and globally ubiquitous internet, all entities responsible for the governance of domains must allocate their lower-level domains with competence and discipline following the basic principle of decentralized governance. The governance and operation of a country code top-level domain is delegated to the governing and operating entity of the relevant country or territory. There are great differences among these entities in domain allocation policy, fees, discipline, and technical competence. The undertaking of governing a global infrastructure requiring high integrity, such as the internet, on the basic principle of decentralized governance is unprecedented. To enable this governance to work well, it is necessary to set up proper objectives for the governance of country domains, and to use highly transparent criteria for a multi-faceted evaluation of how far these objectives have been achieved. This article presents a set of country domain governance indicators which is intended to be used for the construction of a safe and secure ubiquitous global network.     

Preparation and properties of HZr2P3O12 and related compounds

HZr₂P₃O₁₂ (H-form) was prepared in air at 650° C by de-ammoniation of NH₄Zr₂P₃O₁₂ (NH₄-form) in order to study properties of proton in the NaZr₂P₃O₁₂-type structure. Hydration of H-form took place at 70° C, 0.15 GPa, and the final product is (H₃O)Zr₂P₃O₁₂·O·17H₂O (H₃O-form). H- and H₃O-forms reacted with alkali chloride solutions at 25° C. Rates of the exchange reactions were studied as a function of water content of H- and H₃O-bearing compounds. The H-form showed an excellent selectivity for univalent cations in the order: ammonium < potassium < rubidium sodium, lithium.     

A similarity measure between patterns with nonindependent attributes

A generalized version of a set-theoretical measure for obtaining similarities between patterns with nonindependent attributes is presented. The dependence here is given by the pairwise correlation. Since the proposed measure needs no assumption of attribute independence, the resulting similarity values can reflect directly the relationships between the attributes.     

Dynamic scaling and ultrasonic attenuation in 4He near the superfluid transition point

Attenuation of first sound has been measured in ⁴He under saturated vapor pressure near the lambda temperature T at frequencies /2 ranging from 10.2 to 271 MHz. The frequency dependence of the critical part of the attenuation is determined and the dynamic scaling hypothesis is examined. Above the lambda point, it is found that the critical attenuation is described by a scaling function (, ) = ^1+y F(), where = ₀^–x and = T/T – 1, with the results x = 1.02±0.05 and y = 0.33±0.03. The characteristic frequency of the order-parameter fluctuation with the wave number k equal to the inverse correlation length is then proportional to ^x , which is in an excellent agreement with the prediction of dynamic scaling. Below the lambda point, a characteristic relaxation time or times shorter than previously expected at lower frequencies appears to exist in the present frequency range.Based on a Ph.D dissertation submitted by K. Tozaki to the University of Tokyo (1977).     

Formation of layer-like voids in irradiated polytrioxane

The formation of voids and defects is investigated by X-ray diffraction methods, by weight loss measurement and by electron microscopy, for an irradiated polytrioxane (PTOX) obtained by the-ray-induced polymerization of trioxane in the solid state. The main reasons for the formation of the layer-like voids are transverse decomposition at a selective point accessible to the radiation in the micro-fibrils, and the subsequent extensible depolymerization which may occur from the unstable chain end with increase of the radiation dose. The analysis of the SAXS curve for the irradiated PTOX, according to Tsvankin's method gives reasonable results for the void structure, where the reduction of the sub-crystal fraction and also the weight loss of the sample by irradiation are taken into account.     

Oxidative Decomposition of N,N'-Dimethylformamide over Pt Catalysts with H2 Addition to the Feed

Catalysis of decomposition of dilute N, N'-dimethylformamide was explored. Among the catalysts investigated, Pt displayed the highest activity at low temperatures (~200 °C) and DMF conversion was promoted by H₂ addition to the feed. As the Pt support material, H-ZSM-5 exhibited the best performance at around 200 °C in terms of harmless decomposition.     

New carbon composites containing ultrafine Fe,Co, or Ni particles. 1. Facile synthesis by pyrolysis of organometallic polymers

Uniformly dispersed, air-stable carbon composites containing ultrafine α-Fe, Co, or Ni particles were obtained by a careful two-step thermal degradation of a copolymer of acrylonitrile (AN) and 2,4-hexadienyl-[tri(carbonyl)iron] acrylate. Carbonization yields were 45–55% and metal particle size ranged from 80 to 120 nm. Analogous degradation of the acrylonitrile copolymer with CoCl₂(AN)₂, CoCl₂(4-vinylpyridine)₂, or Ni(bis-styrene carboxylate) gave similar composites containing β-Co (18 nm), β-Co (55 nm), or cubic Ni (52 nm) particles, respectively, with lower carbonization yields. Other salient features noted for the metal-containing composites are progressive graphitization promoted by catalysis of nascent metal species at low temperature, microporous structures with surface areas of 75 and 55 m² g^?1 for Co and Ni composites, respectively, high electrical conductivities (10–10² S cm^?1), ferromagnetism, and catalysis in the decomposition of H₂O₂.     

Peeling Behavior and Spalling Resistance of Bonded Bidirectional Fiber Reinforced Polymer Sheets

This paper presents the peeling behavior and spalling resistant effect of bidirectional fiber reinforced polymer (FRP) sheets externally bonded to concrete surfaces. Experimental investigations are carried out through a series of newly designed punching-peeling tests. A wide range of variables, such as FRP sheet layers and fiber direction, plate constraint, concrete strength, adhesives, bond length of FRP sheets, diameter of indenter, and types of fibers, are considered in the experimental investigation. Theoretical study is also conducted for the specimens. Interfacial fracture energy is calculated analytically using a membrane-peeling method. It is realized that only two material parameters, i.e., the interfacial fracture energy of the FRP-concrete interface and the tensile stiffness of FRP sheets, are necessary to represent the interfacial spalling resistant behavior. Finally, the theoretical results are validated by comparing with experimental results. Comparison of theoretical to experimental results shows that the proposed theoretical model is satisfactory in reasonably and accurately predicting the peeling behavior and spalling resistant capacity of bidirectional FRP sheets bonded to concrete surface.     

Thermal management with self-rewetting fluids

The present paper describes the results of a series of microgravity experiments on thermal management device, actually wickless heat pipes, with using the so-called “self t-rewetting fluids” (dilute aqueous solutions of high carbon alcohols) as a working fluid. Although most of liquids show a decrease in the surface tension with increasing temperature, self-rewetting fluids show exceptionally an increase in the surface tension with increasing temperature. This particular characteristic allows for a spontaneous liquid supply to hotter interface by the thermocapillary flow. When liquid/vapor phase change takes place, furthermore, additional Marangoni effect due to concentration gradient by the preferential evaporation of alcohol-rich composition in the aqueous solutions is induced. A considerably strong liquid inflow to dry patch or thin film is therefore expected at three-phase interline or liquid/vapor interface. One of the most promising applications of the self-rewetting fluids in space is wickless heat pipes in which condensate spontaneously returns to evaporation region by enhanced Marangoni effect. Demonstrational experiments on the fluid behavior in a transparent glass tube wickless heat pipe were conducted in JAMIC, and spontaneous liquid return velocities were measured. The present authors then performed parabolic flight experiments on heat transfer characteristics of prototype wickless copper heat pipes, and the performance was compared with ordinary heat pipe having wick structure and with other working fluid.