A guide to vision-based map building

This paper describes a simple vision-based mapping system for mobile robot navigation in an unknown outdoor environment, consistent with the efforts of Georgia Tech's team for the DARPA-sponsored Learning Applied to Ground Robots (LAGR) project. This approach, which has been robust to different environments and responsive to time-critical constraints, is a good example of robotics in practice.     

Discrete geometry methods in processing complicated graphical information

The development of efficient techniques for converting information obtained from complicated graphical documents into a digital form is considered. It is shown that the use of discrete geometry methods make it possible to improve the efficiency of many technological stages. The work was supported by the Russian Foundation for Basic Research, project no. 00-15-96018 and by the Integration Foundation, project no. K-03392.     

Table-Free Bridging

Simple interconnection of high-speed local area networks (LAN's) can be accomplished without special technology through the use of table-free bridges. Self-guided frame routing allows frames to trace specific routes through bridged LAN's without requiring bridges to maintain address tables or perform table lookups. As a result, the technique applies to networks regardless of their operating speed or topological configuration and requires no interbridge protocols. The paper discusses a method known as source routing that provides tablefree bridging and self-guided frame routing for LAN's. Participation by the bridges that interconnect pairs of LAN's and by the stations whose frames they forward is described. Possible frame formats are shown as enhancements to the standard frame formats of the IEEE 802 and ISO 8802 local area networks.     

General solution of one-dimensional,time dependent coupled heat flow systems

A new, powerful method of analysis, involving the combined use of finite integral transform and finite element techniques, is presented for the solution of time dependent heat flow systems composed of many one-dimensional elements connected through the nodes. This method leads to an eigenvalue problem which is not of the conventional Sturm-Liouville type. A procedure for the determination of the eigenvalues is described. The solution obtained is in the form of an infinite series and contains quasi-steady and transient terms. The general solution obtained can be applied in the mathematical modelling of many engineering applications such as the determination of the penetration of the daily temperature cycle into buildings, the analysis of heat transfer in array of extended surfaces in compact heat exchangers, and many others.     

Stress and stability analysis of toroidal shells

A finite element formulation applicable to the general shell of revolution is presented for the stress and stability analysis of toroidal pressure vessels under hydrostatic pressure. Considering the follower force effect of the external pressure, linear bifurcation buckling loads and corresponding mode shapes have been obtained in both axially and equatorially symmetric as well as antisymmetric buckling modes. Calculated critical values are compared with results of other investigations.     

Dominant negative alleles of SEC10 reveal distinct domains involved in secretion and morphogenesis in yeast

The accurate targeting of secretory vesicles to distinct sites on the plasma membrane is necessary to achieve polarized growth and to establish specialized domains at the surface of eukaryotic cells. Members of a protein complex required for exocytosis, the exocyst, have been localized to regions of active secretion in the budding yeast Saccharomyces cerevisiae where they may function to specify sites on the plasma membrane for vesicle docking and fusion. In this study we have addressed the function of one member of the exocyst complex, Sec10p. We have identified two functional domains of Sec10p that act in a dominant-negative manner to inhibit cell growth upon overexpression. Phenotypic and biochemical analysis of the dominant-negative mutants points to a bifunctional role for Sec10p. One domain, consisting of the amino-terminal two-thirds of Sec10p directly interacts with Sec15p, another exocyst component. Overexpression of this domain displaces the full-length Sec10 from the exocyst complex, resulting in a block in exocytosis and an accumulation of secretory vesicles. The carboxy-terminal domain of Sec10p does not interact with other members of the exocyst complex and expression of this domain does not cause a secretory defect. Rather, this mutant results in the formation of elongated cells, suggesting that the second domain of Sec10p is required for morphogenesis, perhaps regulating the reorientation of the secretory pathway from the tip of the emerging daughter cell toward the mother-daughter connection during cell cycle progression.     

The influence of selenium and neuroleptics on the rat brain nuclear regulatory mechanism in carcinogenesis

alpha-Crystallins possess molecular chaperone properties and are one of the most abundant of the lenticular proteins. Posttranslational modifications of these proteins have been implicated as a possible etiology of human cataracts. This article will review current knowledge concerning the effects of known posttranslational modifications upon the molecular chaperone properties and aggregation behavior of alpha-A and alpha-B crystallin. Based upon these effects, experimental approaches will be discussed that may be useful in the development of reagents that may selectively inhibit the cataractogenic process in the aging human lens.     

Efficacy of monensin for the prevention of subclinical ketosis in lactating dairy cows

A total of 1010 dry cows and pregnant heifers was randomly selected from 25 dairy farms near Guelph, Ontario, Canada to receive either a controlled-release capsule of monensin or a placebo at 3 wk prior to expected calving. Serum samples were obtained at the time of treatment administration, and both serum and milk samples were collected at wk 1, 2, 3, 6, and 9 postcalving. The threshold used to define subclinical ketosis was selected a priori at a concentration of > or = 1200 mumol/L of beta-hydroxybutyrate. Using this threshold, the prevalence and incidence of subclinical ketosis were significantly reduced (50%) by monensin treatment. The duration of subclinical ketosis for cows that had been treated with monensin was also shorter than that for cows treated with the placebo. Monensin treatment significantly reduced the incidence of subclinical ketosis when the threshold was defined using higher concentrations of serum beta-hydroxybutyrate (1400 and 2000 mumol/L). In addition, monensin significantly reduced the prevalence of positive milk ketone tests.