[This retracts the article on p. 242 in vol. 8.].

In our discussion of mutual exclusion so far, we have considered atomic access to a single object. What if we wish to atomically access multiple objects. For instance, what if we wish to atomically remove an item from the input buffer and put it in the echo buffer? The high-level constructs such as monitors and path expressions do not give users of shared objects flexibility in defining the uni...

The frame problem arises in considering the logical structure of a robot's beliefs. It has been known for some years, but only recently has much progress been made. The problem is described and discussed. Various suggested methods for its solution are outlined, and described in a uniform notation. Finally, brief consideration is given to the problem of adjusting a belief system in the face of e...

been shown to form bilayer vesicles (cationic liposomes) and have been applied to gene delivery. Cationic vesicles designed for that purpose are generally intrinsically unstable. Although application of cationic liposomes has also been anticipated for the delivery of drugs, peptides, vitamins and lipids and other biologically active compounds to biological cells and tissues, liposomes used for ...