Design and Optimization of Full Comparator Based on Quantum‐Dot Cellular Automata

Quantum‐dot cellular automata (QCA) is one of the few alternative computing platforms that has the potential to be a promising technology because of higher speed, smaller size, and lower power consumption in comparison with CMOS technology. This letter proposes an optimized full comparator for implementation in QCA. The proposed design is compared with previous works in terms of complexity, area, and delay. In comparison with the best previous full comparator, our design has 64% and 85% improvement in cell count and area, respectively. Also, it is implemented with only one clock cycle. The obtained results show that our full comparator is more efficient in terms of cell count, complexity, area, and delay compared to the previous designs. Therefore, this structure can be simply used in designing QCA‐based circuits.     

Pathways to digital business models: The connection of sensing and seizing in business model innovation

Digital business model innovation (BMI) is critical to achieving and sustaining competitiveness in technology-driven environments. In those environments, firms must not only sense changes to identify opportunities but also effectively seize them in BMI. Therefore, sensing and seizing cannot be considered as isolated dynamic capabilities, but must be combined for successful BMI. However, research on sensing and seizing does not offer compelling suggestions for firms that struggle with connecting both while pursuing digital BMI. We use qualitative configurational analysis (QCA) to analyze a sample of 49 case studies on digital BMI to identify the antecedents that firms sense before seizing these changes with digital BMI. Based on ten configurations of sensing (represented by six antecedents) and seizing (represented by four BMI types), we explain the relationship between sensed antecedents and seized digital BMI. In addition, we derived four variables that explain “what” and “how” firms connect sensing and seizing. Based on the sensing-seizing connection, we introduce consolidating BMI as a new type of BMI unique to the digital context. This novel type enables firms to exploit and explore new BMs and subsequent digital BMIs through the means of digital infrastructure. This study extends the understanding of how different business models emerge and how firms create digital BMIs.     

Design of dual-edge triggered flip-flops based on quantum-dot cellular automata

Quantum-dot cellular automata (QCA) technology has been widely considered as an alternative to complementary metal-oxide-semiconductor (CMOS) due to QCA’s inherent merits.Many interesting QCA-based logic circuits with smaller feature size,higher operating frequency,and lower power consumption than CMOS have been presented.However,QCA is limited in its sequential circuit design with high performance flip-flops.Based on a brief introduction of QCA and dual-edge triggered (DET) flip-flop,we propose two original QCA-based D and JK DET flip-flops,offering the same data throughput of corresponding single-edge triggered (SET) flip-flops at half the clock pulse frequency.The logic functionality of the two proposed flip-flops is verified with the QCADesigner tool.All the proposed QCA-based DET flip-flops show higher performance than their SET counterparts in terms of data throughput.Furthermore,compared with a previous DET D flip-flop,the number of cells,covered area,and time delay of the proposed DET D flip-flop are reduced by 20.5%,23.5%,and 25%,respectively.By using a lower clock pulse frequency,the proposed DET flip-flops are promising for constructing QCA sequential circuits and systems with high performance.     

Successful pathway for locally driven fuel cell electric vehicle adoption: Early evidence from South Korea

South Korea is an outstanding pioneer of fuel cell electric vehicle (FCEV) technology, an industry that is fundamental to the hydrogen ecosystem. This study aims to explore possible pathways for the successful adoption of FCEV in the local region. By using the fuzzy-set quality comparative analysis (fs/QCA) method, we identify three auspicious pathways based on the 16 regional cases in Korea. We find that, first, a large number of hydrogen (H₂) stations will lead to successful FCEV adoption (H₂ STATION→FCEV). Second, the combination of high levels of greenhouse gases(GHGs) and the local government-driven future construction plans of H₂ stations can also be a remarkable pathway (GHGs1 PLAN→FCEV). Lastly, a combination of high levels of GHGs and subsidies can be another compelling pathway (GHGs1 SUBSIDIES→FCEV). This study provides early evidence of FCEVs adoption and can be of use to latecomer countries to the hydrogen economy.     

Adder design using 5-input majority gate in a novel “Multilayer Gate Design Paradigm” for Quantum Dot Cellular Automata Circuits

This paper proposes a novel design paradigm for circuits designed in quantum dot cellular automata (QCA) technology. Previously reported QCA circuits in the literature have generally been designed in a single layer which is the main logical block in which the inverter and majority gate are on the base layer, except for the parts where multilayer wire crossing was used. In this paper the concept of multilayer wire crossing has been extended to design logic gates in multilayers. Using a 5-input majority gate in a multilayer, a 1-bit and 2-bit adder have been designed in the proposed multilayer gate design paradigm. A comparison has been made with some adders reported previously in the literature and it has been shown that circuits designed in the proposed design paradigm are much more efficient in terms of area, the requirement of QCA cells in the design and the input-output delay of the circuit. Over all, the availability of one additional spatial dimension makes the design process much more flexible and there is scope for the customizability of logic gate designs to make the circuit compact.     

基于定性比较分析法的高校学生学习效果的研究——以大学生“JavaScript”课程为例

提升学习效果是把控高校人才培养质量的重要手段。本文从"教"和"学"两个维度,以CH高校2017级电子商务专业的"JavaScript"课程为例,采用定性比较分析法(QCA)探索学习效果提升的路径和必要条件。结果表明:教师教学准备与计划和学生学习态度与动机是学习效果提升的必要条件,并且"教"与"学"的条件变量可以产生两种逻辑组合即路径以提升学习效果。     

价值链视角下哈萨克斯坦农业发展影响因素组态与路径研究——基于QCA方法的组态分析

自“一带一路”倡议提出以来,中国与哈萨克斯坦农业合作更加密切,但这种合作能否在激烈的国际市场竞争环境中进一步发展,农业投资领域的合理选择意义重大。论文从价值链视角出发,将农业价值链细分为生产链、物流链、信息链、营销链、创新链5条具有代表性的链条,以2019年哈萨克斯坦17个地州市的数据为研究样本,运用模糊集定性比较分析法（fsQCA）对哈萨克斯坦农业发展的影响因素组态与路径进行分析,研究发现：1）产销互链是形成哈萨克斯坦高水平农业价值链的主要驱动因素,该国高水平农业价值链下存在的两种条件组态分别是“生产链*营销链*（～信息链）*（～创新链）”和“生产链*物流链*营销链*（～创新链）”;2）导致哈萨克斯坦低水平农业价值链的路径则分为落后产能制约型和非农产业导向型,其中落后产能制约型的条件组态包括“（～生产链）*（～物流链）*（～信息链）”和“（～生产链）*物流链*信息链*（～营销链）*创新链”两种条件组态,非农产业导向型的条件组态则是“生产链*物流链*信息链*营销链*创新链”。结果表明：生产链和营销链是哈萨克斯坦目前农业发展的主要驱动因素,而创新链是制约该国农业高质量发展的主要瓶颈,物流链和信息链则具有发展潜力。针对以上结论提出应重点依托哈萨克斯坦部分地州市农业生产和营销方面的优势,积极发挥我国农业技术、信息技术和物流基础设施建设方面的优势,持续深化中哈双方在农业全产业链上的互补性合作,在帮助哈方摆脱“农业转型困境”的同时实现合作共赢。     

基于QCA方法的PPP项目资本结构影响因素研究

为给PPP项目资本结构决策提供更为可靠的依据,通过广义最小二乘回归分析得到PPP项目资本结构的显著影响因素,采用QCA方法得到影响PPP项目资本结构的不同影响因素组合。研究结果表明:债券市值和税收总额与PPP项目杠杆率呈负相关;最有可能带来高杠杆率的影响因素组合有3种:最终交由公共部门运营且总投资额高、最终交由公共部门运营且通货膨胀率高、最终由私人部门运营且债务提供者较多。结论可为PPP项目发起人确定资本结构提供决策依据,同时也可为PPP项目资本结构研究提供新的视角。     

基于QCA的装配式建筑区域发展影响因素构型分析

通过文献分析,以各省市社会经济发展状况为契合点,提取出影响地区装配式建筑发展的5个前因条件因素。以24个省级行政区为样本,应用清晰集定性比较分析方法(csQCA)对各地区装配式发展模式进行探索。最后,验证装配式建筑发展影响因素与其发展状况之间存在非对称因果关系,全国大力发展装配式建筑是可行的,各地区在制定发展装配式建筑政策体系时应该有所侧重。