Latency Optimized Asynchronous Early Output Ripple Carry Adder based on Delay-Insensitive Dual-Rail Data Encoding

Asynchronous circuits employing delay-insensitive codes for data representation i.e. encoding and following a 4-phase return-to-zero protocol for handshaking are generally robust. Depending upon whether a single delay-insensitive code or multiple delay-insensitive code(s) are used for data encoding, the encoding scheme is called homogeneous or heterogeneous delay-insensitive data encoding. This article proposes a new latency optimized early output asynchronous ripple carry adder (RCA) that utilizes single-bit asynchronous full adders (SAFAs) and dual-bit asynchronous full adders (DAFAs) which incorporate redundant logic and are based on the delay-insensitive dual-rail code i.e. homogeneous data encoding, and follow a 4-phase return-to-zero handshaking. Amongst various RCA, carry lookahead adder (CLA), and carry select adder (CSLA) designs, which are based on homogeneous or heterogeneous delay-insensitive data encodings which correspond to the weak-indication or the early output timing model, the proposed early output asynchronous RCA that incorporates SAFAs and DAFAs with redundant logic is found to result in reduced latency for a dual-operand addition operation. In particular, for a 32-bit asynchronous RCA, utilizing 15 stages of DAFAs and 2 stages of SAFAs leads to reduced latency. The theoretical worst-case latencies of the different asynchronous adders were calculated by taking into account the typical gate delays of a 32/28nm CMOS digital cell library, and a comparison is made with their practical worst-case latencies estimated. The theoretical and practical worst-case latencies show a close correlation....Comment: arXiv admin note: text overlap with arXiv:1704.0761

Asynchronous Early Output Dual-Bit Full Adders Based on Homogeneous and Heterogeneous Delay-Insensitive Data Encoding

This paper presents the designs of asynchronous early output dual-bit full adders without and with redundant logic (implicit) corresponding to homogeneous and heterogeneous delay-insensitive data encoding. For homogeneous delay-insensitive data encoding only dual-rail i.e. 1-of-2 code is used, and for heterogeneous delay-insensitive data encoding 1-of-2 and 1-of-4 codes are used. The 4-phase return-to-zero protocol is used for handshaking. To demonstrate the merits of the proposed dual-bit full adder designs, 32-bit ripple carry adders (RCAs) are constructed comprising dual-bit full adders. The proposed dual-bit full adders based 32-bit RCAs incorporating redundant logic feature reduced latency and area compared to their non-redundant counterparts with no accompanying power penalty. In comparison with the weakly indicating 32-bit RCA constructed using homogeneously encoded dual-bit full adders containing redundant logic, the early output 32-bit RCA comprising the proposed homogeneously encoded dual-bit full adders with redundant logic reports corresponding reductions in latency and area by 22.2% and 15.1% with no associated power penalty. On the other hand, the early output 32-bit RCA constructed using the proposed heterogeneously encoded dual-bit full adder which incorporates redundant logic reports respective decreases in latency and area than the weakly indicating 32-bit RCA that consists of heterogeneously encoded dual-bit full adders with redundant logic by 21.5% and 21.3% with nil power overhead. The simulation results obtained are based on a 32/28nm CMOS process technology

A MULTI-ATTRIBUTE MODEL OF PUBLIC ACCEPTANCE OF GENETICALLY MODIFIED ORGANISMS

Using Fishbein's multiattribute model as a theoretical background, this paper develops an empirical model to assess and identify attributes of agrobiotechnology and individual characteristics determining public acceptance of biotech foods. This paper uses a database collected in the United States and United Kingdom in November, 2000.Consumer/Household Economics, Research and Development/Tech Change/Emerging Technologies,

Role of Demographics and Health Attitude in Consumers' Nutrition Consideration in Food Selection

A nationwide on-line survey of 3,000 households was conducted. Households were randomly selected from the database of 400,000 households who make up Ipsos-NPD marketing research panel. The purpose of this study is to examine how a household meal planners perception of the importance of various dietary components in selecting food items is influenced by the persons or the households socio-demographic factors and health attitude. Annual household income affected fat, calcium, and cholesterol considerations significantly but did not make any impact on the consideration of salt when consumers selected food items. Hence, the result implies that as income level increases, household meal planners are more likely to be concerned about fat, calcium and cholesterol. Older household meal planners were more likely to consider salt, calcium and cholesterols than their younger counterparts. Health attitude of the household meal planners significantly influenced their nutritional concerns. Thos meal planners who read nutritional labels on food products and changed diet to reduce the risk of disease were concerned about all four types of nutritional factors included in the study.Nutrition consideration, health attitude, socio-demographical factors, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,

UK Consumers' Willingness-to-Accept (WTA) GM Food

Our study uses contingent valuation survey data (WTA and WTP) collected in the UK to examine consumers' behavioral intention with regard to GM food. In particular, we characterize respondents who selected "Don't Know" and "Protest" options in WTP questions in terms of what they would do when offered discount for GM food.Contingent valuation, WTA, WTP, genetically modified food, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

AN EVALUATION OF CONSUMER ACCEPTANCE OF GENETICALLY MODIFIED FOOD: WILLINGNESS-TO-PAY (WTP) VS. WILLINGNESS-TO-ACCEPT (WTA).

Using Heckman's sample selection model, consumer willingness-to-pay (accept) premium (discount) for non-GM (GM) cereals was analyzed. Results showed that consumers who were indifferent to the risk of consuming GM foods behaved differently compared to those who were willing-to-pay (accept) premium (discount) for non-GM (GM) cereals.Consumer/Household Economics,