应用遗传算法的多机器人协调动作学习

本文力图做出的系统是应用遗传算法使多机器人学习可以动作协调而总体实现最多的搬运。多机器人移动的环境采用图表表示，移动的规则是用遗传算法优化制订的，在两预定结点之间的往返次数取为适合度，用计算机构造环境并进行仿真，结果表明多机器人协调作学习时可视情况需要而互相让路。     

A mutation in NPS1/STH1, an essential gene encoding a component of a novel chromatin-remodeling complex RSC, alters the chromatin structure of Saccharomyces cerevisiae centromeres

The NPS1/STH1 gene encodes a nuclear protein essential for the progression of G2/M phase in Saccharomyces cerevisiae . Nps1p shares homology to Snf2/Swi2p, a subunit of a protein complex known as the SNF/SWI complex. Recently, Nps1p was found to be a component of a protein complex termed RSC (3) essential for mitotic growth, whereas its function is unknown. We isolated a temperature-sensitive mutant allele of NPS1 , nps1-105, and found that the mutation increases the sensitivity to thiabendazole (TBZ). At the restrictive temperature, nps1-105 arrested at the G2/M phase in MAD1-dependent manner and missegregated the mini-chromosome with higher frequency than the wild type cells. The nuclease digestion of the chromatin of the mutant cells revealed that the mutation causes the alteration of the chromatin structure around centromeres at the restrictive temperature. The results suggested that, in the nps1-105 mutant, impaired chromatin structure surrounding centromeres may lead to an impairment of kinetochore function and the cells arrest at G2/M phase through the spindle-assembly checkpoint system.     

Modulation depth enhancement for highly sensitive electro-optic RF near-field measurement

A modulation depth enhancement technique for highly sensitive electro-optic (EO) sensing of RF near-fields is presented. This technique increases EO signal intensity without increasing total power received by a photodiode (PD). Therefore, sensitivity limitation owing to saturation of the PD can be avoided. Sensitivity improvement of 20 dB compared to the conventional configuration is successfully achieved     

The role of boron in low-temperature synthesis of indialite (α-Mg2Al4Si5O18) by sol–gel process

Powder and pellets composed mainly of indialite (α-Mg2Al4Si5O18) with 2.1 wt% added B2O3 were prepared by a sol–gel process using metal salts as raw materials. When heated at 900°C for 6 h, the pellets showed a relative density of 91.4% of ideal cordierite (β-Mg2Al4Si5O18), a Vickers hardness of 1080 and a relative dielectric constant of 5.0 (at 1 MHz), which was the same value as that of cordierite. Magic angle spinning nuclear magnetic resonance measurements of 29Si, 27Al and 11B showed that boron disturbed the formation of the Si–O–Al network below 300°C and broke the network between 700 and 800°C. The high homogeneity and fluidity caused by the melting helped indialite to crystallize directly from the amorphous state between 800 and 850°C. This revised version was published online in November 2006 with corrections to the Cover Date.     

Crystal structure of 3-isopropylmalate dehydrogenase from the moderate facultative thermophile, Bacillus coagulans: two strategies for thermostabilization of protein structures

The crystal structure of 3-isopropylmalate dehydrogenase from the moderate facultative thermophile Bacillus coagulans (BcIPMDH) has been determined by the X-ray method. BcIPMDH is a dimeric enzyme composed of two identical subunits, each of which takes an open alpha/beta structure with 11 alpha-helices and 14 beta-strands. The polypeptide is folded into two domains. The first domain is composed of residues 1-101 and 257-356, and the second domain, of residues 102-256. The latter domains of the two subunits are associated with one another by a dyad axis to make the dimer, locally forming a beta-sheet and a four-helix bundle. As compared with the structure of the enzyme from the extreme thermophile Thermus thermophilus (TtIPMDH), a new short beta-sheet (residues 329-330 and 340-341) absent in TtIPMDH is formed by the insertion of 5 residues in BcIPMDH. In terms of determinants for thermostabilization, both consistent and inconsistent changes were found between the two enzymes. The regions including inconsistent changes are formed by different usages of the determinants for stabilizing the loops at different levels. Those in BcIPMDH contain some structural redundancies in length of amino acid sequence and flexibility of residues, which seem to be unnecessary for the enzymatic reaction. Such redundancies are also found in the primary structure of the enzyme of the mesophile Bacillus subtilis, but these parts are more stabilized in BcIPMDH by hydrogen bonds and salt bridges. On the other hand, TtIPMDH is stabilized by reducing such redundant parts. This contrast suggests that different strategies may be preferred for thermostabilization, depending on temperature.     

The origin of extended dislocations induced by high-dose ion implantation

The origin and the generation mechanism of ion implantation-induced dislocations is investigated with an Si/sub 3/N/sub 4/ band line/space pattern. The Si/sub 3/N/sub 4/ film-edge stress not only causes dislocation propagation but also causes the formation and deformation of extended dislocations at the initial stage of annealing. The behavior is clarified that the dislocation loops are deformed into pattern-edge dislocation half loops, which accumulate at the film edge and are punched out from the edge.     

Novel design procedure of broad-band multilayer antireflectioncoatings for optical and optoelectronic devices

A novel design procedure of broad-band multilayer antireflection (AR) coatings for optical and optoelectronic devices is proposed. The design algorithm is based on the optical admittance detuning, with the bandwidth of finite reflectivity as a new merit function. Coating structures consist of only two materials with nonquarter-wave thicknesses. Numerical mappings on the four-layer structure showed four optimizing regions where an optimized four-layer AR coating on 1.55 μm GaInAs-AlGaInAs MQW semiconductor laser facet was predicted to have a broad bandwidth of 106 mm for a reflectivity of less than 10^-5. TiO₂ and SiO₂ were electron-beam (EB) evaporated to form the four-layer AR coating on glass and InP substrates with an ion-beam assist and a real time in situ optical thickness monitor and experimentally verify its broad-band performance     

A Neural Network Parallel Algorithm for Meeting Schedule Problems

A parallel algorithm for solving meeting schedule problems is presented in this paper where the problem is NP-complete. The proposed system is composed of two maximum neural networks which interact with each other. One is an M × S neural network to assign meetings to available time slots on a timetable where M andS are the number of meetings and the number of time slots, respectively. The other is an M × P neural network to assign persons to the meetings where P is the number of persons. The simulation results show that the state of the system always converges to one of the solutions. Our empirical study shows that the solution quality of the proposed algorithm does not degrade with the problem size.     

Analysis of a 36.2 kb DNA sequence including the right telomere of chromosome VI from Saccharomyces cerevisiae

The nucleotide sequence of a 36.2-kb distal region containing the right telomere of chromosome VI was determined. Both strands of DNA cloned into cosmid clone 9965 and plasmid clone pEL174P2 were sequenced with an average redundancy of 7.9 per base pair, by both dye primer and dye terminator cycle sequencing methods. The G+C content of the sequence was found to be 37.9%. Eighteen open reading frames (ORFs) longer than 100 amino acids were detected. Four of these ORFs (9965orfR017, 9965orfF016, 9965orfR009 and 9965orfF003) were found to encode previously identified genes (YMR31, PRE4, NIN1 and HXK1, respectively). Six ORFs (9965orfR013, 9965orfF018, 9965orfF006, 9965orfR014, 9965orfF013 and 9965orfR020) were found to be homologous to hypothetical 121.4-kDa protein in the BCK 5' region, Bacillus subtilis DnaJ protein, hypothetical Trp-Asp repeats containing protein in DBP3-MRPL27, putative mitochondrial carrier YBR291C protein, Salmonella typhimurium nicotinate-nucleotide pyrophosphorylase, and Escherichia coli cystathionine beta-lyase, respectively. The putative proteins encoded by 9965orfF018, 9965orfR014 and 9965orfR020 were found to be, respectively, a new member of the family of DnaJ-like proteins, the mitochondrial carrier protein and cystathionine lyase.