Brave induction: a logical framework for learning from incomplete information

This paper introduces a novel logical framework for concept-learning called brave induction. Brave induction uses brave inference for induction and is useful for learning from incomplete information. Brave induction is weaker than explanatory induction which is normally used in inductive logic programming, and is stronger than learning from satisfiability, a general setting of concept-learning in clausal logic. We first investigate formal properties of brave induction, then develop an algorithm for computing hypotheses in full clausal theories. Next we extend the framework to induction in nonmonotonic logic programs. We analyze computational complexity of decision problems for induction on propositional theories. Further, we provide examples of problem solving by brave induction in systems biology, requirement engineering, and multiagent negotiation.     

Effect of cold rolling on the superconducting and electronic properties of two amorphous alloys; Nb50Zr35Si15 and Nb70Zr15Si15

The effect of cold rolling on the superconducting properties was examined for amorphous Nb₅₀Zr₃₅Si₁₅ and Nb₇₀Zr₁₅Si₁₅ superconductors. Cold rolling to 10 to 20% reduction in thickness results in a rise of superconducting transition temperature (T _c) and a decrease in transition width (T _c), upper critical field gradient near , critical current density [J _c(H)] and normal electrical resistivity (_n). Changes of about 7% forT _c 33% for T _c, 12% for and 70% forJ _c(H) are found. The rise ofT _c upon cold rolling was considered to originate from the increase in the electron-phonon coupling constant () due to an increase in the electronic density of states at the Fermi level [N(E _f)] and a decrease in the phonon frequency (), while the decreases in T_c,J _c(H) and _n were attributed to the decrease in fluxoid pinning force due to an increase in homogeneity in the amorphous structure. From the results described above, the following two conclusions were derived: (a) cold rolling causes changes in electronic and phonon-states in the quenched amorphous phase, and (b) deformation upon cold rolling occurs not only in the coarse deformation bands observable by optical microscopy, but also on a much finer scale comparable to the coherence length (7.7 nm).     

Superconductivity of Zr-Nb-Si amorphous alloys

Superconducting amorphous alloys with high strength and good ductility have been found in rapidly quenched alloys of the Zr-Nb-Si system. These alloys were produced in a continuous ribbon form of 1 to 2 mm width and 0.02 to 0.03 mm thickness using a modified single roller quenching apparatus. The amorphous alloys were formed over the whole composition range between zirconium and niobium, but the silicon content was limited to the relatively narrow range between about 12 and 24 at%. All the amorphous alloys showed a superconducting transition whose temperature, T _c, increased from 2.31 to 4.20 K with increasing niobium content or with decreasing silicon content. The upper critical magnetic field, H _c2, and the critical current density, J _c, for Zr₁₅Nb₇₀Si₁₅ alloy were of the order of 4.5 Tesla(T) and 5.5×10⁶ A m^–2 at 1.5 K in the absence of applied field. The upper critical field gradient at T _c, , and the electrical resistivity at 4.2 K, _n, decreased from 2.89 to 2.10 T K^–1 and from 2.70 to 1.80m, respectively, with the amount of niobium. The Debye temperature, _D, the electron-phonon coupling constant, , and the bare density of electronic states at the Fermi level, N(E _f ) were calculated from the experimentally measured values of _n, , Young's modulus and density by using the strong-coupling theories. From the comparison of T _c with their calculated parameters, it was found that is the most dominant parameter for T _c. The GL parameter, , and the GL coherence length, _GL(0), were estimated to be 70 to 100 and about 7.6 nm, respectively, from the experimental values of and _n by using the GLAG theory and hence it is concluded that the present amorphous alloys are an extremely dirty type-II superconductor having a very weak flux pinning force.     

Diel vertical migration and nutrient transport of the dinoflagellate Peridinium bipes f. occultatum in a thermally stratified reservoir

Field observations were conducted with respect to the vertical migration of the dinoflagellate Peridinium bipes and its influence on vertical nutrient transport in a stratified reservoir. P. bipes migrated vertically with circadian rhythms; that is, P. bipes migrated downward and accumulated in the top layer of the hypolimnion from evening to night and then migrated upward and accumulated in the epilimnion in the early morning. In the top layer of the hypolimnion, a rapid decrease in nutrient concentration was observed in the evening, presumably due to uptake by P. bipes. Active migration from the epilimnion to the top of the hypolimnion was also suggested by estimation of the descent velocity of P. bipes, which was advantageous for the uptake of nutrients. Moreover, based on the equilibrium of forces during migration, the energy cost of vertical migration could be inferred to be negligible. The results suggest that active vertical migration of P. bipes played an important role in nutrient transport between the hypolimnion and the epilimnion in a stratified reservoir.     

ILP turns 20

Inductive Logic Programming (ILP) is an area of Machine Learning which has now reached its twentieth year. Using the analogy of a human biography this paper recalls the development of the subject from its infancy through childhood and teenage years. We show how in each phase ILP has been characterised by an attempt to extend theory and implementations in tandem with the development of novel and challenging real-world applications. Lastly, by projection we suggest directions for research which will help the subject coming of age.     

Efficient semi-supervised learning on locally informative multiple graphs

We address an issue of semi-supervised learning on multiple graphs, over which informative subgraphs are distributed. One application under this setting can be found in molecular biology, where different types of gene networks are generated depending upon experiments. Here an important problem is to annotate unknown genes by using functionally known genes, which connect to unknown genes in gene networks, in which informative parts vary over networks. We present a powerful, time-efficient approach for this problem by combining soft spectral clustering with label propagation for multiple graphs. We demonstrate the effectiveness and efficiency of our approach using both synthetic and real biological datasets.     

A high‐performance sorting algorithm for multicore single‐instruction multiple‐data processors

Many sorting algorithms have been studied in the past, but there are only a few algorithms that can effectively exploit both single‐instruction multiple‐data (SIMD) instructions and thread‐level parallelism. In this paper, we propose a new high‐performance sorting algorithm, called aligned‐access sort (AA‐sort), that exploits both the SIMD instructions and thread‐level parallelism available on today's multicore processors. Our algorithm consists of two phases, an in‐core sorting phase and an out‐of‐core merging phase. The in‐core sorting phase uses our new sorting algorithm that extends combsort to exploit SIMD instructions. The out‐of‐core algorithm is based on mergesort with our novel vectorized merging algorithm. Both phases can take advantage of SIMD instructions. The key to high performance is eliminating unaligned memory accesses that would reduce the effectiveness of SIMD instructions in both phases. We implemented and evaluated the AA‐sort on PowerPC 970MP and Cell Broadband Engine platforms. In summary, a sequential version of the AA‐sort using SIMD instructions outperformed IBM's optimized sequential sorting library by 1.8 times and bitonic mergesort using SIMD instructions by 3.3 times on PowerPC 970MP when sorting 32 million random 32‐bit integers. Also, a parallel version of AA‐sort demonstrated better scalability with increasing numbers of cores than a parallel version of bitonic mergesort on both platforms. Copyright © 2011 John Wiley & Sons, Ltd.     

Fractional power approximation and its generation

For an analog simulating system, an approximating system is proposed. Its mathematical form is expressed by an algebraic equation:

$\text{? (x) ≈ α + β χ + γχ}{}^{\mathrm{k}}$

with four parameters given by real numbers. Their values can be determined so as to satisfy a best fit in a Chebyshev sense. Then, the accuracy is of the same order with that obtained by any kind of ordinary power series up to terms o f the third order. It is noticeable that a given function can be accurately approximated by this equation without destroying its uniform continuity.As its electronic system, it is possible to utilize forward current-voltage characteristics o f p-n diodes near their origins. Different functions can be produced by adjusting an amount o f ordinary resistances connected to diodes in series.     

Thermomechanical behavior of Ti-Ni shape memory alloy films deposited by DC magnetron sputtering

In this study, thermomechanical properties of titanium-nickel (Ti-Ni) shape memory alloy (SMA) films are investigated in order to derive constitutive relations. Ti-Ni SMA films, deposited by DC magnetron sputtering under controlled film composition, are characterized by uniaxial tensile tests. At room temperature (R.T.), Ti-Ni films having Ti contents less than 50 at% exhibit superelastic behavior, and those having Ti contents greater than 50 at% exhibit shape memory behavior. However, the Ni—53.2 at% Ti film fractured at a tensile strain of 0.8% because of an increase in brittleness with increasing Ti content. At elevated temperatures, Ti-Ni films having Ti contents of 50.2 to 52.6 at% undergo phase change from martensite to austenite. The Young's modulus of the Ti-Ni films depends on temperature at each phase, regardless of film composition. Film composition does, however, affect the measured material constants b_A, b_M, c_A, and c_M. Stress-strain curves calculated from the constructed constitutive equation closely agree with those obtained from tensile tests, for both the martensite and austenite phases. The constitutive equations are expected to find great utility in the design of Ti-Ni film-actuated microelectromechanical systems (MEMS).     

Optical pulse compression based on stationary rescaled pulse propagation in a comblike profiled fiber

In this paper, optical pulse compression using a comblike profiled fiber (CPF) is theoretically and experimentally studied, in which highly nonlinear fibers and single-mode fibers are alternately concatenated. Stationary rescaled pulse (SRP), is the main focus, which is a recently discovered nonlinear stationary pulse in CPF. The fundamental characteristics of SRP are investigated, and SRP propagation is applied to the design of the CPF pulse compressor. Using the proposed design method, the specifications of the CPF can easily be controlled, such as the compression ratio per step of the CPF or the pedestal of the output pulse. Two experimental results of pulse compression using the CPF based on the proposed design method are shown: 1) pulse compression with a large compression ratio per step of the CPF and 2) low-pedestal and wideband wavelength-tunable compression. A parametric noise-amplification phenomenon occurring in a compression process for an optical pulse sequence is also numerically analyzed.