An application of Markov potential theory to Markovian decision processes

The aim of this paper is to identify the denumerable stochastic systems which have an optimal strategy, namely, to give general sufficient conditions of the existence of an optimal strategy for denumerable Markovian decision processes. The aim is accomplished by using Markov potential theory and showing the range of the validity of a method to find an optimal strategy called Howard's technique. Since Markov potential theory helps to characterize the properties of evaluations of strategies on such processes, it plays an important role to find the sufficient conditions mentioned above

For Markov potential theory, new concepts are introduced such as absorbable chains, quasi-potentials, etc., and using them, sufficient conditions for the existence of a solution of the equation x = f+Px are generalized to the one's for cyclic chains and multi-chains

The results obtained in this paper are as follows : if a system represents a strong Markov chain for any strategy, then there exists an optimal strategy with respect to the total or the mean expected earnings, and for any stochastic system there exists an optimal strategy with respect to the discounted total expected earnings.     

Preparation and Thermal Properties of Dense Polycrystalline Oxyhydroxyapatite

Solution-grown crystals of hydroxyapatite were sintered into polycrystalline oxyhydroxyapatite bodies, using the range 1050 to 1450°C. The heat capacity, thermal diffusivity, and thermal conductivity of the sintered bodies were measured by the laser flash method at 130–1000 K. The sintered bodies were 94.4 to 99.4% of theoretical density and 0.8 to 12 μm in grain size. Sintering is accompanied by grain growth and by vacancy formation and cell contraction due to thermal dehydration. Typical values of the heat capacity, thermal diffusivity, and thermal conductivity at room temperature are 0.73 J/g K, 0.0057 cm²/s and 0.013 J/s cm K, respectively. Low-temperature thermal conductivity increased with increasing temperature, similarly to that of amorphous solids. This odd behavior is discussed in terms of phonon mean free path.     

LIPID CLASSES, FATTY ACID COMPOSITIONS AND TRIACYLGLYCEROL MOLECULAR SPECIES FROM ADZUKI BEANS (VIGNA ANGULARIS)

The lipids extracted from adzuki beans grown in Japan were classified by thin-layer chromatography (TLC) into eight fractions. Molecular species and fatty acid distributions of triacylglycerols (TAGs) isolated from the total lipids in the beans were determined from a combination of argentation-TLC and gas chromatography. The major lipid components were phospholipids (PL; 63.5%) and TAG (21.2%), while hydrocarbons (5.1%), steryl esters (7.5%), free fatty acids (0.9%), diacylglycerols (1.3%) and monoacylglycerols (0.5%) were also present in minor proportions. Both major samples had high amounts of total unsaturated fatty acids, representing 62.1% for TAG and 65.9% for PL. Seventeen different molecular species were detected. The major TAG components were SMD (5.0%), S₂T (19.3%), SD₂ (13.8%), SMT (9.3%), MD₂ (4.5%), SDT (7.0%), D₃ (8.8%) and ST₂ (15.9%), where S, M, D and T denote a saturated fatty acid, a monoene, a diene and a triene, respectively.

PRACTICAL APPLICATIONS

This article describes the characteristics of lipid components, fatty acid compositions as well as the profiles of triacylglycerol (TAG) molecular species of adzuki beans. α-Linolenic (18:3 n -3) acid was detected as 24.8, 21.2 and 15.2% in the TAG, total lipids and phospholipids, respectively. The oil from legumes, except the profitable fatty acid content, could be a potential source of tocopherols. The data obtained in this study would be useful to both consumers and producers for manufacturing traditional adzuki confectionaries ( wagashi ) in Japan and elsewhere.     

Microstructures of SrTiO3 Internal Boundary Layer Capacitors During and After Processing and Resultant Electrical Properties

The microstructure of strontium titanate internal boundary layer capacitors at various stages in their processing was studied by transmission electron microscopy of rapidly quenched and normally cooled samples. Compositions containing excess TiO₂, Al₂O₃, and SiO₂ have a completely wetting liquid phase at the sintering temperature; during cooling Ti_nO_{2 n −1}, Magneli phases precipitate at multiple grain junctions. Diffused metal oxides and flux (Bi₂O₃, PbO, CuO, and B₂O₃) rapidly penetrate as a liquid phase along boundaries in postsintering heat treatment. This liquid phase disappears during slow cooling.     

Learning automaton as a model to simulate and analyse learning behaviour in rats

A technique is presented for using a learning automaton as a model to simulate and analyse learning behaviour in rats, and the usefulness of this model is illustrated. This automaton was proposed as a learning machine by Tsetlin (1961) and refined by Aso and Kimura (1976). Some learning properties of such an automaton are first examined and it is shown that the automaton can be used to simulate a variety of learning behaviour, composed of several kinds of action, by the proper selection of parameters. Secondly, a mathematical model of the learning experiment carried out in our laboratory with rats is formulated as an interactive system between a learning automaton and its environment. Finally, the effectiveness of the mathematical model is discussed and proved through the simulation and analysis of learning behaviour with multiple actions in a specific rat.     

真空压铸中型腔真空压力的理论计算及试验研究

针对真空压铸中型腔真空压力的下降规律进行了理论计算和试验研究。针对具体的真空系统进行了型腔排气理论曲线和实测曲线的对比,验证了这种计算方法的可行性,指出了真空压铸为了达到理想的型腔真空压力对于低速工艺选择的限制要求,并提出了一种通过计算理论排气时间来对真空系统设计和低速工艺制定进行优化的方法。     

Synthesis and Thermal Stability of Aluminum Titanate Solid Solutions

Aluminum titanate solid solutions with empirical formulas of Al₂Ti_1-xZr_xO₅, Al_6(2-x)(6+x)Si_6x/(6+x)□_6x/(6+x)TiO₅, and Al_2(1-x)Mg_xTi_1+xO₅ were synthesized by reaction sintering and annealed at 900° to 1300°C in air to evaluate the thermal stability. Substitution of Al in Al₂TiO₅ by Si and 2Al by Mg and Ti ions to form solid solutions such as AI_{6(2-x)/(6+x)l-Si}6x/(6+x)□_6x/(6+x)TiO₅, and Al_2(1-x)Mg_xTi_1+xO₅ was effective in controlling the thermal decomposition, but substitution of Ti by Zr had little effect.     

Calorimetric Determination of the Amylose Content of Starches Based on Formation and Melting of the Amylose-Lysolecithin Complex

Amylose-lysolecithin complexes, formed in an exothermic reaction when amylose or starches are heated with water and lysolecithin, melt at temperatures near 107°C. With excess lysolecithin present, formation of the maximum amount of amylose complex requires cooling after the first heating (during which gelatinization of starch takes place), and then reheating. An amylose with chain length of 300 glucose units took up 14% lysolecithin; the enthalpy of melting of this complex, observed by differential scanning calorimetry, was 5.9 cal/g amylose. Amylose content of a starch was calculated from the enthalpy of melting of its lysolecithin complex. Amylose contents for potato, tapioca, lima bean, wrinkled pea, amylomaize and waxy maize starches agreed with values obtained by iodine binding. Amylose contents of maize and wheat starches were larger than obtained by iodine binding, and in better agreement with amylose contents obtained by fractionation.     

Running Torque of Ball Bearings with Polymer Lubricant (Effect of the Enclosure Form of Polymer Lubricant)

This article deals with the running torque of ball bearings with polymer lubricant (solid composite material composed of plastic impregnated with a large amount of oil or grease). The results of the experiment showed that the measured running torque of ball bearings with polymer lubricant was affected by the enclosure form of the polymer lubricant. With regard to ball bearings with different enclosure forms of the polymer lubricant, the measured running torque difference was not affected significantly by the rotational speeds or the axial loads. The analytical results showed that the running torque difference was caused mainly by the friction (depending on the enclosure form of the polymer lubricant) between the balls and the polymer lubricant (or cage).     

Proposal of Series‐Parallel Continuously Regulated Chopper Suitable for Auxiliary Power Supply of Railway Vehicle

The conventional auxiliary power supply (APS) of a railway vehicle is directly connected to the catenary through the LC filter. Hence, the switching devices of the APS must have a high breakdown voltage to account for catenary voltage fluctuation. On the other hand, low‐voltage switching devices have better characteristics that are desirable for low‐loss and high‐frequency operation. Therefore, a step‐down converter is incorporated between the LC filter and inverter to adapt to catenary voltage fluctuations when using low‐voltage switching devices. This paper proposes the series‐parallel continuously regulated chopper as a novel step‐down converter. First, the fundamental operation characteristics and output voltage control method of the proposed chopper are introduced. The simulation and experimental results for the fundamental characteristics are then described; the simulation and experimental values were almost the same as the theoretical values. The proposed chopper controls the output voltage at the expected value without dramatic fluctuation regardless of the input voltage fluctuation. In addition, a resonance damping control for a constant power load is proposed. The operational characteristics were considered under different potential distributions or load conditions.