Decidable problems on the strong connectivity of Petri net reachability sets

For a Petri net N and a marking M, let R_N(M) be the set of markings reachable from M and let C_N(M) be the set of markings M′ such that M′ ?R_N(M) and M?R_N(M′)C_N(M) is a strongly connected component of R_N(M) to which M belongs. If R_N(M) = C_N (M), then N is said to be M-reversible, and if N is M-reversible for every marking M, then N is said to be reversible. In this paper the following results are presented. (1) C_N(M) is semilinear and therefore it is decidable whether (i) M′ ?C_N(M), (ii) C_N(M) is a finite set, (iii) C_N(M) ? C_N′(M′), and (iv) given two markings M and M′ such that M ? M′, there is a nonnegative integer k such that M + k(M ? M′) ?R_N(M′). (2) It is decidable whether (i) N is M-reversible or not, and (ii) N is reversible or not. (3) Given a Petri net N and a marking M, we can construct an M-reversible Petri net N′ such that C_N(M) = R_N′(M). (4) The equality problem for the sets of all firing sequences of an M-reversible Petri net N and an M′-reversible Petri net N′ is decidable. And some related problems are discussed.     

Die Endabweichung von Nachfolgesystemen unter Berücksichtigung von Störgeräuschen

Inhalt Die Eigenschaften von einigen Folgesystemen, besonders bei zusätzlichem Störgeräusch, werden untersucht und miteinander verglichen.Praktische Methoden, durch die die quadratische Endabweichung des Systems zu einem Minimum wird, werden vom Verfasser vorgeschlagen.

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Contents The author treats of the characteristics of some servomechanisms, especially the case of input signal including a noise and also compares it with each other.The signal adaptive system which has a minimum square error, proposed in this paper, is very usefull for the practical applications.

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Mit 11 Textabbildungen     

Comparison of the ability of viral protein-expressing plasmid DNAs to protect against influenza

The ability of plasmid DNA encoding various influenza viral proteins from the A/PR/8/34 (H1N1) virus to protect against influenza was compared in BALB/c mice. The plasmid DNA encoded hemagglutinin (HA), neuraminidase (NA), matrix protein (M1), nucleoprotein (NP) or nonstructural protein (NS1) in a chicken beta-actin-based expression vector (pCAGGS). Each DNA was inoculated twice 3 weeks apart at a dose of 1 microgram per mouse by particle-mediated DNA transfer to the epidermis (gene gun). Seven days after a second immunization, mice were challenged with the homologous virus and the ability of each DNA to protect mice from influenza was evaluated by decreased lung virus titers and increased survival. Mice, given HA- or NA-expressing DNA, induced a high level of specific antibody response and protected well against the challenge virus. On the other hand, mice given M1-, NP-, or NS1-DNA failed to provide protection, although M1- and NP-DNAs did induce detectable antibody responses. These results indicate that both HA- and NA-expressing DNAs for the surface glycoproteins are most protective against influenza from among the various viral protein-expressing DNAs used here.     

Dural-pial arteriovenous malformation after sinus thrombosis

BACKGROUND: We report an unusual case of acquired dural-pial arteriovenous malformation (AVM) following sinus thrombosis. CASE DESCRIPTION: Initial angiography performed in a 39-year-old man showed thrombosis of the superior sagittal sinus (SSS) and the right transverse sinus (TS) but no vascular malformations. Follow-up angiography 29 months later revealed recanalization of the SSS and the TS, retrograde cortical venous drainage which suggested that thrombosis of the sinuses probably propagated into the adjacent parietal cortical veins, and development of a dural-pial AVM at or near the site of thrombi in more than one cortical vein. Complete surgical excision of the lesion was accomplished without neurological deterioration. CONCLUSIONS: The present case suggests the possibility that the pial AVM is not only a congenital condition but also may develop as an acquired lesion.     

Modeling of diffusive mass transport in micropores in cement based materials

In order to predict long-term leaching behavior of cement constituents for safety assessments of radioactive waste disposal, we modeled diffusive mass transport in micropores in cement based materials. Based on available knowledge on the pore structure, we developed a transport porosity model that enables us to estimate effective porosity available for diffusion (transport porosity) in cement based materials. We microscopically examined the pore structure of hardened cement pastes to partially verify the model. Effective diffusivities of tritiated water in hardened cement pastes were also obtained experimentally, and were shown to be proportional to the estimated transport porosity.     

Features of a control blade degradation observed in situ during severe accident conditions in boiling water reactors

In the present paper, new results using in situ video are presented regarding boiling water reactor (BWR) control blade degradation up to 1750 K at the beginning of a nuclear severe accident. Energy-dispersive X-ray spectrometry (EDS) mapping indicated stratification of the absorber blade melt with formation of a chromium and boride-enriched layer. High-content-B- and C-containing material with increased melting temperature acted like a shielding and was found to prevent further relocation of control blade claddings. The interacted layers around the B₄C-granules prevented direct steam attack of residual B₄C. The results provide new insights for understanding of the absorber blade degradation mechanism under reducing conditions specific to Fukushima Dai-Ichi Unit 2 resulting from prolonged steam starvation.     

Effects of customer response to fashion product stockout on holding costs,order sizes,and profitability in omnichannel retailing

In retailing practice, customers may actively respond in one of the following ways after experiencing stockout of a preferred brand: switch to a substitutable brand, switch to another store (where the preferred brand could be available), or delay purchase (backlogging). This paper presents a model of active customer responses to stockout of fashion products. In the single‐period model, a retailer maximizes profit by selling two substitutable brands through two different stores. Analytical results and numerical experiments suggest that active response to stockout increase the retailer's profitability due to (a) additional revenue from backlogging and brand and store switching and (b) decrease in optimal order size resulting in lower holding costs. Omnichannel fulfillment offers additional opportunities for retailers to benefit from active responses to stockout.     

Synthesis and conformational studies of polymers and copolymers of O,O′-dimethyl-l-β-3,4-dihydroxyphenyl-α-alanine with γ-benzyl-l-glutamate

Eight different copolymers of $\text{O,O′-}\text{dimethyl-}\text{l}\text{-β-3,4-}\text{dihydroxyphenyl}\text{-α-}\text{alanine}$ ($\text{O,O′-}\text{dimethyl-}\text{l}\text{-}\text{Dopa}$) and γ-benzyl-l-glutamate with degrees of polymerization of 320-80 have been synthesized by the N-carboxyanhydride method. From the results obtained by a study of the optical rotatory dispersion and circular dichroism for the copolymer series, the conformation of $\text{poly}\text{(O,O′-}\text{dimethyl-}\text{l}\text{-Dopa}\text{)}$ is a right-handed helix in helicogenic solvents such as chloroform, dioxane or 2-chloroethanol. Copolymers containing less than 50 mol % glutamate show a circular dichroism peak at 285 nm suggesting stacking of aromatic groups in the side chain. $\text{Poly}\text{(O,O′-}\text{dimethyl-}\text{l}\text{-Dopa}\text{)}$ is in the random coil structure in trifluoroacetic acid or hexafluoroacetone. The results were compared with those of $\text{poly}\text{(O,O′-}\text{dicarbobenzoxy-}\text{l}\text{-Dopa}\text{)}$ and poly(l-Dopa).