Hierarchies of data base languages: An example

In view of a manufacturer's investments, commercially available data base systems usually offer comparatively general-purpose interfaces. In order to adapt these interfaces to the special problems of a particular user considerable effort in time, money and personnel is required by the user. Therefore, one might ask whether, (a) construction rules may be found which simplify the process of adaptation and (b) new interfaces may be defined which are both more problem-oriented and still economical enough to be standardized. Based on the notion of hierarchy of abstract machines, this paper attempts to present a possible approach to the solution of these questions. In particular, a set-theoretic and a natural-German interface are suggested. These interfaces as well as some implementation aspects will be motivated, defined, and illustrated by means of a system currently in operation at the university of Karlsruhe. The advantages of a set-theoretic approach as well as the problems associated with a natural language interface will be discussed.     

Formation of PTFE-like films in CF4 microwave plasmas

The study focuses on the deposition of films from pure CF₄ using low pressure microwave plasmas (MW) on polystyrene substrate with a subsequent examination of the resulting surfaces. It is generally accepted, that the F/C-ratio of the precursor molecule plays an important role for the outcome of a low pressure plasma process, or the balance between fluorocarbon deposition and material etching. Surprisingly, thin film formation could be observed using MW gas discharges in CF₄, a typical etching gas. Coatings with a thickness of at least 10 nm are formed. The films are polytetrafluoroethylene (PTFE)-like, characterized by an F/C-ratio of 1.8, and a hydrophobic surface with a water contact angle of 110°.     

Artificial compound eye: a survey of the state-of-the-art

An artificial compound eye system is the bionic system of natural compound eyes with much wider field-of-view, better capacity to detect moving objects and higher sensitivity to light intensity than ordinary single-aperture eyes. In recent years, renewed attention has been paid to the artificial compound eyes, due to their better characteristics inheriting from insect compound eyes than ordinary optical imaging systems. This paper provides a comprehensive survey of the state-of-the-art work on artificial compound eyes. This review starts from natural compound eyes to artificial compound eyes including their system design, theoretical development and applications. The survey of artificial compound eyes is developed in terms of two main types: planar and curved artificial compound eyes. Finally, the most promising future research developments are highlighted.     

Non-invasive mobile monitoring of meat quality

Detailed investigations into the time-dependent changes of pork meat quality and composition have been carried out using standard analytical techniques and Raman and fluorescence spectroscopy. Characteristic changes in soluble protein content, microbial load and biogenic amine content have been measured in the time period from slaughter up to 20 to 30 days post mortem on samples of porcine musculus longissimus dorsi. Characteristic behaviour indicative of a deterioration of meat quality and an increase in microorganism population on the meat surface has been observed. Fluorescence and Raman optical signals have been identified which change over this time period, correlating with the standard measurements and these can be used as indicators of meat properties. These signals can be measured rapidly and without the destruction of the meat sample allowing non-invasive testing. The combination of these two powerful measurement techniques provides a pathway to comprehensive meat quality monitoring. Furthermore we have developed a hardware concept for carrying out these spectroscopic measurements using a compact and light handheld device and we present concepts for the use of such a device in the logistic chain in combination with a transponder chip and integrated sensors which provide product identification and information about storage conditions along the entire logistic chain to the supermarket shelf. Received: September 16, 2008; accepted: October 5, 2008