Showing papers on "Encoding (memory) published in 1972"

Optimum State Assignment for Synchronous Sequential Circuits

Abstract: The problem of encoding the internal states of synchronous sequential switching circuits so as to minimize the combinational network cost is treated. Cost is defined as the number of AND-OR inputs required in the two-level implementation of each memory element input equation separately ( i.e., the cost is not reduced initially by the existence of common terms between equations). An algorithm has been developed that considers implicitly all distinct state-assignment schemes for a given state table, thus ensuring that the state assignment that results in the least "cost" combinational network is selected. Since any optimum state-assignment scheme is dependent on the type of memory element, the algorithm is designed for use with J-K flip-flop memory elements because of their wide use and versatility.

Device ensuring the automatic stoppage of a guided moving body at desired positions not defined by exterior reference or guide marks

Abstract: A system for stopping a body in one of several possible stop zones along a limited path. The system includes a servo, including a drive, controlled by a comparator, and a special position encoding arrangement including a binary disc encoder for giving a fine indication of position and a second disc encoder with tracks defining successive sectors corresponding to the number of stop zones, a track of which the angular segments correspond to the stop zones and are each within one of the sectors and a further track having segments angularly overlapping the stop zone segments. The various tracks can provide signals in anticipation of an approach to a desired stopping position.

Feedback in Sequential Machine Realizations

Abstract: In this paper we study feedback in sequential machines that are implemented with trigger or set-reset flip-flop memory elements. A method is given for determining when a machine can be implemented with either trigger or set?reset flip-flop memory elements where the feedback in the machine is given by a Boolean function f. Several results are presented that compare the feedback when a machine is implemented with different memory elements. It is shown that if a sequential machine can be implemented with unit delay memory elements with feedback function f, then it can be realized with set-reset flip-flop with the same feedback function f. For completely specified machines, it is shown that if a machine implemented with trigger flip-flop has no feedback, then the some machine implemented with unit delays will have feedback. Conversely, if an implementation with unit delays has no feedback, then an implementation with trigger flip-flops will have feedback.

Free recall: organization and long-term memory

Abstract: Free recall was examined In order to (1) examine the differences between the clustering of items from a l i s t with an a priori structure and the subjective organization from a l i s t of unrelated words and to (2) describe organizational processes in terms of theoretical constructs. Three sections of experiments found: (1) that two manipulations of organization of lists of unrelated words had asymmetric effects on recognition and recall performance; (2) that order of output and recall performance from two lists of unrelated words was predicted by similarity judgments data; and (3) that order of output from two specially-constructed lists was described by a hierarchical arrangement of categories. The data were interpreted as showing three commonalities between the clustering of items from a l i s t with an a priori structure and the subjective organization from a l i s t of unrelated words. These were: (1) asymmetric effects on recognition and recall can be produced by manipulations of both categorized and unrelated lists;'(2) order of output can be predicted by similarity judgments data for both categorized and unrelated l i s t s ; and (3) free recall performance can be predicted by conformity to category structures for both categorized and unrelated l i s t s . An informal model of free recall was proposed. The model had the following properties which were abstracted from the experiments: (1) the internal structure of organization was described as hierarchical; (2) the processing which results in this structure was based on similarities between items; and (3) the output was described as representing different processes dependent upon whether recall or recognition tests are used.

Number Encoding and Matching in Short-Term Memory.

Abstract: The effects of types of both memorized items and probes (digit, word, and dot pattern), using Sternberg's character-recognition procedure, were studied. Reaction time (RT) was a linear function of the set size of memorized items consistent with a serial search model. Response type (positive or negative) affected the encoding time (intercept of RT function) or probes only, and was explained by a rechecking operation. Finally, probe types had effects on both search rate (slope) and encoding time, but types of memorized items affected neither. These results were discussed in terms of the encoded information and its relttions to search operation. (Author) U.S. DEPARTMENT OF HEALTH. EDUCATIONS. WELFARE NATIONAL INSTITUTE OF EDUCATION THIS DC'UMENT HAS BEEN REPRO DUCED EXACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION ORIGIN AT1NG IT POINTS OF VIEW OR OPINIONS r-4 STATED 00 NOT NECESSARILY REPRE SENT OFFICIAL Nil iONAL INSTITUTE OF Lr. EDUCATION POSITION OR POI-ICY C\J !umber encoding and matching ire short-term memory C.7) Leonard Katz and David A. Wicklund r-t In a simple match taak, Posner and Mitchell (1967) presented LLJ pairs of letters, capital or small, to which S responded "same" or "different" as quickly as possible. They found that physical matches (both letters either capital or small) were about 8041mec. faster than name matches when the stimuli were presented simulta. neously. But the advantage of physical matches disappeared when the stimuli were separated by 2 sec. or more (Posner & Keels, 1967; Posner, Boiea, Eiohelman & Taylor, 1969). From these results the nature of storage nodes which follow after the visual presentation was inferred; visual and name components of a visual stimulus overlap within memory. If the second stimulus is visually identical to the first, memorized, stimulus, Ss may respond "same" by using physical identity alone without going to the name level. If the visual representation is no longer active, S must then match at the name level. The efficiency of this visual code for matches decline to that of the same code

Adaptive statistical encoding of d.p.c.m.-coded videotelephone signals

Abstract: Adaptive statistical encoding of d.p.c.m.-coded video-telephone signals is considered. The need for an adaptive statistical encoder to operate on short-term batch statistics is explained and the effect on the bit rate of limiting the number of codes employed by the statistical encoder is reported.