Logic Design Method Research Articles

Logic Networks of Carry–Save Adders

logic networks of carry–save adders such as high-speed multipliers, multioperand adders, and double-rail input parallel adders are designed based on the parallel adders with a minimum number of NOR gates discussed in [1]. After a discussion of the derivation of carry–save adder modules (CSAM's) by the integer programming logic design method, general design procedures are illustrated with example networks. Compared to conventional networks of carry–save adders, the derived networks of carry–save adder modules (NOCSAM's) have the advantages of fewer gates, fewer connections, and faster operation. In particular, the parallel adder of NOR gates in double-rail input logic obtained has six gates and 15½ connections per stage, whereas the previously known best design under the same condition requires six gates and 17 connections per stage with the same carry propagation delay.

Minimum Parallel Binary Adders with NOR (NAND) Gates

Parallel binary adders of n bits long in single-rail input logic which have a minimum number of NOR gates are derived in this paper. The minimality of the number of NOR gates is proved for an arbitrary value of n. Also, it is proved that the adders must be a cascade of basic modules and that there exist many different types of basic modules. These adders have fewer gates and shorter net gate delays (or fewer connections) than the widely used carry-ripple adders which are a cascade of one-bit full adders. Design procedures of such adders are described, based on the integer-programming logic design method. There are many solutions but adders with few connections and those with few net gate delays (all these adders have the minimum number of gates) are shown as important examples. Altbough these adders are designed with NOR gates, the results in this paper are applicable to adders with NAND gates by duality conversion.

Points from letters: Frequency of cervical smears

<h3>SUMMARY</h3> Excessive increase in blood glucose level after eating increases the risk of macroangiopathy, and a method for not increasing the postprandial blood glucose level is desired. However, a logical design method of the dietary ingestion pattern controlling the postprandial blood glucose 2 level has not yet been established. We constructed a mathematical model of blood glucose control by oral glucose ingestion in 3 healthy human subjects, used the model to predict an optimal glucose ingestion pattern, and showed that the optimal ingestion pattern minimized the peak value of blood glucose level. Subjects orally ingested 3 doses of glucose by bolus or over 2 hours, and blood glucose, insulin, C-peptide and incretins were measured for 4 hours. We constructed an ordinary differential equation model that reproduced the time course data of the blood glucose and blood hormone levels. Using the model, we predicted that intermittent ingestion 30 minutes apart was the optimal glucose ingestion patterns that minimized the peak value of blood glucose level. We confirmed with subjects that this intermittent pattern decreased the peak value of blood glucose level. This approach could be applied to design optimal dietary ingestion patterns. <h3>In Brief</h3> As a forward problem, we measured blood glucose and hormones in three human subjects after oral glucose ingestion and constructed a mathematical model of blood glucose control. As an inverse problem, we used the model to predict the optimal oral glucose ingestion pattern that minimized the peak value of blood glucose level, and validated the pattern with the subjects. <h3>Highlights</h3> Modeling blood glucose concentrations predicts an intermittent ingestion pattern is optimal Human validation shows ingestion at 30-minute intervals limits peak blood glucose We provide a strategy to design optimal dietary ingestion patterns

Boiling of liquids in a compact plate-fin heat exchanger

Prior to this study, no logical design method has existed for boiling heat transfer in compact, plate-fin, heat exchangers. This paper shows that a single-fin analysis can be used to predict the performance. Confirming tests were made with boiling Freon-113 and isopropanol heated by condensing steam, using a commercial compact heat exchanger having an 8·25 × 8·25 × 7·87 cm core which contained 11200 fins on the boiling side and 23 660 fins on the condensing side. The flow passages were 3·78 × 1·46 mm on the boiling side and 2·39 × 1·43 mm on the condensing side.

Orthogonal Expansion of Many-Valued Logical Functions and its Application to their Realization with a Single-Threshold Element

The orthogonal expansion of many-valued logical functions is described and some approximate forms derived from it are discussed. A method of logical design of many-valued functions, especially threshold functions, using a single-threshold element is proposed based on the approximate forms.

Comments on "Basic Properties and a Construction Method for Fail-Safe Logical Systems"

The paper by Mine and Kogal appears to have some unstated assumptions and inconsistencies which affect the validity of their claim to have presented "an effective method of logical design for fail-safe systems."

Basic Properties and a Construction Method for Fail-Safe Logical Systems

In this paper, the authors study ``fail-safe'' properties of logical systems, finding the conditions that the basic logical functions of fail-safe logical systems should satisfy and also identifying the allowable failures for the basic logical function circuits. With these results, the authors present a systematic representation of fail-safe logical systems, and an effective method of logical design for fail-safe systems.

The generation of symmetrical duct velocity profiles of high uniform shear

The logical design method of Owen &amp; Zienkiewicz (1957), for the generation of linear shear flow, is successfully applied to the case of symmetrical velocity profiles in a two-dimensional duct. Shear parameters as high as 0·8 (corresponding to $\hat{V}| \overline {V} = 1\cdot4$) are obtained experimentally. Some slight modification to the theoretical grid spacing is required because of the non-uniformity of the upstream flow.The decay of the profiles is confined to that due to the developing boundary layer and to the breakdown of the physically impossible condition at the centre, where symmetry implies a change in sign of the uniform shear.