In this paper, a multistable modified fourth-order autonomous Chua’s chaotic system is investigated. In addition to the dynamic characteristics of the third-order Chua’s chaotic (...) class='Hi'>system itself, what interests us is that this modified fourth-order autonomous Chua’s chaotic system has five different types of coexisting attractors: double-scroll, single band chaotic attractor, period-4 limit cycle, period-2 limit cycle, and period-1 limit cycle. Then, an inductorless modified fourth-order autonomous Chua’s chaotic circuit is proposed. The active elements as well as the synthetic inductor employed in this circuit are designed using second-generation current conveyors. The reason for using CCIIs is that they have high conversion rate and operation speed, which enable the circuit to work at a higher frequency range. The Multisim simulations confirm the theoretical estimates of the performance of the proposed circuit. Finally, using RK-4 numerical algorithm of VHDL 32-bit IQ-Math floating-point number format, the inductorless modified fourth-order autonomous Chua’s chaotic system is implemented on FPGA for the development of embedded engineering applications based on chaos. The system is simulated and synthesized on Virtex-6 FPGA chip. The maximum operating frequency of modified Chua’s chaotic oscillator based on FPGA is 180.180 MHz. This study demonstrates that the hardware-based multistable modified fourth-order autonomous Chua’s chaotic system is a very good source of entropy and can be applied to various embedded systems based on chaos, including secure communication, cryptography, and random number generator. (shrink)
Background: When the contagious COVID-19 spread worldwide, the frontline staff faced unprecedented excessive work pressure and expectations of all of the society. Objective: The aim was (...) class='Hi'>to explore healthcare workers’ stress and influencing factors when caring for COVID-19 patients from an altruistic perspective. Methods: A cross-sectional, descriptive study was conducted in a tertiary hospital during the outbreak of COVID-19 between February and March 2020 in Wuhan, the capital city of Hubei province in China. Data were collected from 1208 healthcare workers. Descriptive statistics and multiple linear regression were used to analyze the data. Ethical considerations: Research ethics approval was obtained from Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology. Written informed consent was also received from participants. Results: Less than 60% of participants chose moderate or severe stress on all stressors, indicating a low stress level among healthcare workers. The main source of stress among frontline healthcare workers caring for COVID-19 patients came from the fear of being infected, the fear of family members being infected, and the discomfort caused by protective equipment. Frontline staff who were nurses, were married, and had worked more than 20 days suffered higher stress, whereas rescue staff showed lower stress. Conclusion: The healthcare workers caring for patients with COVID-19 had low stress level, although they still had the fear of being infected or uncomfortable feeling caused by personal protective equipment. A low stress level among healthcare workers indicated their professional devotion and altruism during COVID-19 epidemic. Medical institutions and the government should continue to strengthen infection prevention measures and provide more comprehensive care involving families of frontline healthcare workers, especially nurses and married staff. It will be a lesson to other countries that awaking healthcare workers’ inside motivation and providing necessary support from government and society were significant. (shrink)
This study examines the relationship among the employees–organization pro-environmental values fit, supervisors’ PEVs and employees’ pro-environmental behaviors. Informed by the PEB, organizational values and employee– (...) class='Hi'>organization fit literature, we propose and test hypotheses that under egoistic, altruistic and biosphere-value orientations, E–O PEVs fit versus non-fit have significant effects on employees’ private-sphere PEB and public-sphere PEB, identifying supervisors’ PEVs as a moderator. An empirical investigation indicates that the effect of E–O PEVs fit on employees’ private-sphere PEB and public-sphere PEB varies as the value orientation differs. More specifically, under the context of altruistic and biosphere-value orientations, if the organizational PEVs do not match the employees’ PEVs, especially when the former exceeds the latter, employees’ PEB will rise as the organizational PEVs increase. As for egoistic value orientation, when organizational PEVs exceed employees’ PEVs, not only will public-sphere PEB stop decreasing and tend to stabilize, but also private-sphere PEB will rise to a slight degree. Furthermore, compared with altruistic and biospheric values dimensions, supervisors who promote egoistic PEVs will have a more significant effect on the relationship between global E–O PEVs fit and employees’ PEB. Finally, we suggest that the goals of an organization and its supervisors need to be combined within the actual situation of Chinese corporations to truly implement corporate green practices by balancing the profit goal and the environmental goal. (shrink)
Intensified due to rapid urbanization and global warming-induced high temperature extremes, the urban heat island effect has become a major environmental concern for urban residents. Scientific (...) class='Hi'>methods used to calculate the urban heat island intensity and its alleviation have become urgent requirements for urban development. This study is carried out in Zhongshan District, Dalian City, which has a total area of 43.85 km2 and a 27.5 km-long coastline. The mono-window algorithm was used to retrieve the land surface temperatures, employing Landsat remote sensing images, meteorological data, and building data from 2003, 2008, 2013, and 2019. In addition, the district was divided into local climate zones based on the estimated intensities and spatiotemporal variations of the heat island effect. The results show that, from 2003 to 2019, LCZs A and D shrank by 3.225 km2 and 0.395 km2, respectively, whereas LCZs B, C, and 1–6 expanded by 0.932 km2, 0.632 km2, and 2.056 km2, respectively. During this period, the maximum and minimum LSTs in Zhongshan increased by 1.365°C and 1.104°C, respectively. The LST and UHII levels of all LCZs peaked in 2019. The average LSTs of LCZs A–C increased by 1.610°C, 0.880°C, and 3.830°C, respectively, and those of LCZs 1–6 increased by 2°C–4°C. The UHIIs of LCZs A, C, and D increased by 0.730, 2.950, and 0.344, respectively, and those of LCZs 1–6 increased from 1.370–2.977 to 3.744–5.379. Overall, the regions with high LSTs are spatiotemporally correlated with high building densities. In this study, the land cover was then classified into four types using visual interpretation and object-oriented classification, including forested land, low vegetation, bare ground, and water. Besides, the buildings were categorized as LCZs 1–6, which, respectively, represented low-density low-rises buildings, low-density high-rises buildings, low-density super high-rises buildings, high-density low-rises buildings, high-density high-rises buildings, and high-density super high-rises buildings. (shrink)
The present study examined the behavioral effects of the first-person possessive pronoun. In each trial, a noun was presented to participants after visual presentation of a (...) class='Hi'>possessive pronoun “wo de” or “ta de” , which formed ownership. Half participants were assigned to contextual encoding condition in which they were required to judge whether they liked the item expressed by a noun from the first or third-person perspective. The rest were assigned to perceptual encoding condition in which they were asked to judge what color the noun was. A subsequent recall test was performed. The results showed that there were significant memory and response advantages for nouns in “my” ownership under both conditions. The results were discussed with reference to self-specificity and other effects in the current study. (shrink)
This paper focuses on the robust control of fractional-order economical chaotic system with parametric uncertainties and external disturbances. The dynamical behavior of FOECS is studied by (...) class='Hi'>numerical simulation, and circuit implementations of FOECS are also given. Based on fractional-order Lyapunov stability theorems, a robust adaptive controller, which can guarantee that all signals remain bounded and the tracking error tends to a small region, is designed. The proposed method can be used to control a large range of fractional-order systems with system uncertainties. Fractional-order adaptation laws are constructed to update the estimation of adaptive parameters. Finally, the robustness and effectiveness of our control method are indicated by simulation results. (shrink)
Either in microlevel organizations or macrolevel societies, the individuals acquire benefits or payoffs by forming interdependency groups linked by common interests. Conducting research on the effects of (...) interdependency groups on the evolution of cooperation could have a better understanding of the social dilemma problem. In this paper, we studied a spatial public goods game with nonlocal interdependency groups where each of participants is located in a two-dimensional square lattice or Watts–Strogatz small-world network with payoffs obtaining from the interactions with nearest neighbors. In terms of the enhancement factor, the effects of group density on the evolutionary cooperation can be quite different. For a low enhancement factor, the cooperation level is a nonmonotonic function with the varying density of interdependency groups in the system, which means a proper density of interdependency groups can best promote the cooperative level. For a moderate enhancement factor, a higher density of interdependency groups can always correspond to a higher cooperative level. However, if the enhancement factor is too high, a high density of interdependency groups can impede the evolutionary cooperation. We give the explanations for the different roles of group density of interdependency by using the transition probabilities of C players into D players as well as the reverse. Our findings are very helpful for the understanding of emergence cooperation as well as the cooperation regulation in the selfish individuals. (shrink)
By introducing a flux-controlled memristor model with absolute value function, a 5D multistable four-wing memristive hyperchaotic system with linear equilibrium points is proposed in this paper (...) class='Hi'>. The dynamic characteristics of the system are studied in terms of equilibrium point, perpetual point, bifurcation diagram, Lyapunov exponential spectrum, phase portraits, and spectral entropy. This system is of the group of systems that have coexisting attractors. In addition, the circuit implementation scheme is also proposed. Then, a secure communication scheme based on the proposed 5D multistable FWMHS with disturbance inputs is designed. Based on parametric modulation theory and Lyapunov stability theory, synchronization and secure communication between the transmitter and receiver are realized and two message signals are recovered by a convenient robust high-order sliding mode adaptive controller. Through the proposed adaptive controller, the unknown parameters can be identified accurately, the gain of the receiver system can be adjusted continuously, and the disturbance inputs of the transmitter and receiver can be suppressed effectively. Thereafter, the convergence of the proposed scheme is proven by means of an appropriate Lyapunov functional and the effectiveness of the theoretical results is testified via numerical simulations. (shrink)
Recent research has uncovered the dark side of creativity by finding that creative individuals are more likely to engage in unethical behavior. However, we argue that not (...) all creative individuals make trouble. Using moral self-regulation theory as our overarching theoretical framework, we examine individuals’ moral identity as a boundary condition and moral disengagement as a mediating mechanism to explain when and how individual creativity is associated with workplace deviant behavior. We conducted two field studies using multi-source data to test our hypotheses. In Study 1, the results indicated that creativity positively predicted moral disengagement for those low in moral identity. In Study 2 with multi-wave data, we replicated the finding that moral identity moderated the effect of creativity on moral disengagement in Study 1 and further revealed that moral disengagement mediated the interactive effects of creativity and moral identity on workplace deviant behavior. The theoretical and practical implications of these findings and directions for future research are discussed. (shrink)
Air quality in China is characterized by significant spatial and temporal differences, which are directly related to local meteorological conditions. This study used air quality monitoring data, (...) namely, the air pollution index and air quality index between 2005 and 2018, together with meteorological data and identified key meteorological factors that affected the spatial and temporal variation of air quality using a random forest algorithm. The spatial and temporal differences in the threshold values of different meteorological factors affecting the concentrations of PM2.5, PM10, SO2, CO, NO2, and O3 were identified. The AQI has the advantages of facilitating higher index values than the API. The air quality showed an improvement from 2005 to 2018. Wind direction and precipitation were the most important meteorological factors affecting the air quality in northern and southern China, respectively, which to some extent reflected the causes and degradation mechanisms of air pollution in the two regions. There were significant spatial and temporal differences in the effects of meteorological factors on the concentrations of different pollutants. The influence of atmospheric pressure on pollutant concentration differed between the east and west. Precipitation and relative humidity in most cities had significant impacts on PM2.5 and PM10. The influence of relative humidity was most significant for SO2 and it also had a great influence on O3, while wind speed had a great influence on NO2. The results of the study confirm the meteorological sensitivity of air quality and provide support for the implementation of regional air pollution prevention and control initiatives. (shrink)
Using 3D seismic attributes and the support of a clay model that served as an analog, we mapped and analyzed a 32 km long, north–south-striking, right (...) class='Hi'>-lateral fault in the Woodford Shale, Anadarko Basin, Oklahoma, USA. Volumetric coherence, dip azimuth, and curvature delineated an approximately 1.5 km wide damage zone with multiple secondary faults, folds, and flexures. The clay analog enabled us to identify these features as belonging to a complex transpressional Riedel structure. We also suggest that the damage zone contains dense subseismic fractures associated with multiscale faulting and secondary folding that may correspond to highly permeable features within the Woodford Shale. (shrink)
In this work, a novel 6D four-wing hyperchaotic system with a line equilibrium based on a flux-controlled memristor model is proposed. The novel system is inspired (...) class='Hi'> from an existing 5D four-wing hyperchaotic system introduced by Zarei. Fundamental properties of the novel system are discussed, and its complex behaviors are characterized using phase portraits, Lyapunov exponential spectrum, bifurcation diagram, and spectral entropy. When a suitable set of parameters are chosen, the system exhibits a rich repertoire of dynamic behaviors including double-period bifurcation of the quasiperiod, a single two-wing, and four-wing chaotic attractors. Further analysis of the novel system shows that the multiple coexisting attractors can be observed with different system parameter values and initial values. Moreover, the feasibility of the proposed mathematical model is also presented by using Multisim simulations based on an electronic analog of the model. Finally, the active control method is used to design the appropriate controller to realize the synchronization between the proposed 6D memristive hyperchaotic system and the 6D hyperchaotic Yang system with different structures. The Routh–Hurwitz criterion is used to prove the rationality of the controller, and the feasibility and effectiveness of the proposed synchronization method are proved by numerical simulations. (shrink)
Based on ideology-infused psychological contract theory and cognitive evaluation theory, this study investigated the curvilinear relationship between ethical leadership and employee creativity. A curvilinear mediation model (...) class='Hi'>was proposed to explain the impact of ethical leadership on creativity, using employee intrinsic motivation as the mediator. Applying a two wave sampling design that consist 258 employees and their leaders, we found that employee creativity improved as ethical leadership increased from low to moderate levels. However, the employee creativity improvement was attenuated when ethical leadership increased from moderate to high levels. Furthermore, the study also revealed that employee intrinsic motivation partially mediated this curvilinear relationship. The theoretical and managerial implications are discussed. (shrink)
A dilemma in interpreting Hui Shi's ten theses is that they are understandable only in the light of relativistic pluralism, which conflicts with his own main (...) class='Hi'>theme of absolutistic monism. However, after a careful investigation of the evolutionary paths of the tense and aspect uses of the temporal adverb fang 方 in classical Chinese language, a construction argument can be made for fang sheng fang si 方 生 方 死. But before presenting this construction argument, we first introduce the dilemma in interpreting the ten theses.Hui Shi's ten theses are listed as follows: 1The ultimately great has no outside, call it the Great One. The ultimately small has no inside, call it the Small One. 2The dimensionless cannot be... (shrink)
Out of 288 Hong Kong cancer patients, 92.3% include themselves in decision-making, 71% prefer joint decision-making: with family, with doctor, with doctor plus family, with (...) family minus doctor, and with doctor minus family. <5% want decision-making by “doctor-alone” and <1% desire decision-making by “family-alone”. Harmony, communication and responsibility are reasons for family participation. Most patients prefer “specialist” for information, followed by “family”, “friends”, and “GP”. Trust in doctors and prospects for controlling/curing disease are important factors in decision-making. Patients want to participate and be listened to rather than make decisions. Doctors should not disclose information to family without patients’ permission, nor withhold information from patient [End Page 109] on family’s request. Only 25% of patients have discussed post-competent treatment with others and 7% have heard of Advance Directive ; 24% refuse to discuss it. After AD has been explained to them, 66% remain reluctant to sign one, preferring to leave oral instructions or appoint family as proxy decision-makers. The family’s decision-making role increases when patients become incompetent. The top reason for signing AD is to receive preferred post-competent treatments, and for not signing it, difficulty with making a prospective decision. The implications of these findings will be discussed. (shrink)
No apology, I imagine, is necessary for the appearance of this translation\nof Marx's "Misere de la Philosophic" On the contrary it is strange\nthat it should (...) not have been published in England before, anu that\nthe translation of his monumental work, the "Capital," tardy as that\nwas, should have yet been made before that of a work which was originally\npublished some twenty years before "Capital" first appeared.\n\n\nIt may be that the translators and editors of the latter work were\nof opinion that in view of the comprehensiveness of "Capital," a\npublication of an English edition of the "Misere de la Philosophic"\nwould be a work of supererogation. Or it may be that they thought\na book so distinctly French—as the "Capital" may be said to be distinctly\nEnglish—and which was, further, exclusively a criticism of a work\nof Proudhon's little known in England—would have slight interest\nfor English readers. On the other hand, the groundwork of the theories\nso fully elaborated in "Capital," apart from its exhaustive analysis\nof the capitalist system of production and distribution, will be\nfound in "Misere." In addition, there are several subjects—notably\nthat of rent—dealt with in this volume which are barely touched upon\nin the single book of " Capital " which has been translated into\nEnglish.\n\n\nMarx's criticism of Proudhon's theory that " the time which is necessary\nto create a commodity indicates exactly its degree of utility," so\nthat " the things of which the production costs the least time are\nthe things which are the most immediately useful," has been matched\nby H. M. Hyndman's crushing refutation of the theory of Final Utility.\nThe subject of rent, too, has been fully dealt with by the latter\nin the same book, " The Economics of Socialism," published, as the\nauthor says, in the hope of furnishing " the rapidly-increasing number\nof students of sociology with a concise and readable statement of\nthe main theories of the scientific school of political economy founded\nby Karl Marx and Friedrich Engels." Neither of these facts, however,\nnecessarily detracts from the value of this older work of Marx's.\nOn the question of rent, after reviewing the Ricardian theory and\nthe many objections which present themselves to that theory, Hyndman\nsays: " It seems, therefore, that a wider definition of the rent\nof land under capitalism is needed than that given by Ricardo, and\nthe following is suggested: — Rent of land is that portion of the\ntotal net revenue which is paid to the landlord for the use of plots\nof land after the average profit on the capital embarked in developing\nsuch land has been deducted." On the question of confiscating rent\nhe says it " would not affect the position of the working portion\nof the community unless the money so obtained were devoted to giving\nthem more amusement, to providing them with better surroundings and\nthe like. ... In fact, the attack upon competitive rents is merely\na capitalist attack. That class sees a considerable income going\noff to a set of people who take no part in the direct exploitation\nof labor; and its representatives are naturally anxious to stop this\nleakage, as they consider it, and to reduce their own taxation for\npublic purposes by appropriating rent to the service of the State.\nThat is all very well for them."\n\n\nOn this point Marx says: " We can understand such economists as Mill,\nCherbulliez, Hilditch and others, demanding that rent should be handed\nover to the State to be used for the remission of taxation. That\nis only the frank expression of the hate which the industrial capitalist\nfeels for the landed proprietor, who appears to him as a useless\nincumbrance, a superfluity in the otherwise harmonious whole of bourgeois\nproduction."\n\n\n" Rent," says Marx, " results from the social relations in which exploitation\nis carried on. It cannot result from the nature, more or less fixed,\nmore or less durable, of land. Rent proceeds from society and not\nfrom the soil."\n\n\nThe criticism of Proudhon's appreciation of gold and silver as the\nfirst manifestation of this theory of " constituted value" should\nbe interesting reading to those admirers of the French Anarchist\nwho yet profess their profound detestation of money and its function.\nSo, too, should his declaration against strikes and combinations\nof workmen. In this we see once more how extremes meet. This declaration\nof Proudhon's would not be out of place in the organ of the Liberty\nand Property Defence League.\n\n\nIn this matter of trade union combination, Marx was scarcely accurate\nin his perception of its development. He clearly did not foresee\nthat the great English trade unions would become fossilised, as it\nwere; and that instead of being a revolutionary force they would\nbecome a reactionary mass, opposing the progress of the mere proletarian\noutside their ranks, as they have done. With the spread of Socialist\nideas among them, however, their exclusive character is being modified,\nand they may even yet take that place in the revolutionary working-class\nmovement which Marx anticipated they would occupy. Given this change\nof attitude, the development must inevitably be along the lines he\npredicted. We are seeing "in face of constantly united capital, the\nmaintenance of the association [becoming] more important and necessary\nfor them than the maintenance of wages," and, further, that the combinations\nof capital are forcing the trade unions to that point where "association\ntakes a political character."\n\n\nIt is scarcely necessary to point out that in this work, written in\n1847, some words have a meaning quite other than that which they\nbear to-day. Thus, for instance, the words "Socialists" and "Socialism,"\nwhere they occur, refer to the utopians—who formulated theories of\na social system independent of the industrial evolution— and to these\ntheories themselves.\n\n\nIn most cases the numerous quotations have been verified and reproduced\nin the original. In some instances, however, they are summaries rather\nthan quotations, and appear ^is translated.\n\n\nA translation jn* necessarily an imperfect presentation of the thoughts,\nideas, and conclusions of the author. In this work I have endeavored\nto adhere as closely as possible to the form and letter, as well\nas the spirit of the original, and to this the indulgent reader is\nasked to ascribe such faults of language as would otherwise merit\nhis censure. (shrink)
To deal with coordination problem of a supply chain consisting of two competitive suppliers and a dominant retailer, considering these factors such as cooperation effort degrees and (...) competition on the supply chain members, we establish a two-stage model considering cooperation effort degrees and competition of the suppliers from the perspectives of decentralized decision and centralized decision and exploit it to discuss the optional decisions and explore the impact of cooperation effort degrees on the profits of supply chain members. Then, we use a group negotiation model to establish a coordination mechanism. The results reveal that the decision variables and overall profit of the supply chain of suppliers and retailers under centralized decisions are better than those under the decentralized decisions. Besides, the degree of competition and price sensitivity have positive and negative effects on the efforts of suppliers and retailers, respectively. Meanwhile, the degree of cooperation between suppliers and retailers affects the profits of supply chain members and the whole supply chain in different degrees. Finally, the proposed value-added profit distribution mechanism can effectively deal with conflict problem and guarantee supply chain members and supply chain to maximize their profits and adopt the centralized decision. (shrink)
Data centers, which provide computing services and gain profits, are indispensable to every city in the information era. They offer computation and storage while consuming energy and (...) generate thermal discharges. To maximize the economic benefit, the existing research studies on the data center workload management mostly leverage the dynamical power model, i.e., the power-aware workload allocation. Nevertheless, we argue that for the complex relationship between the economic benefit and so many attributes, such as computation, energy consumption, thermal distribution, cooling, and equipment life, the thermal distribution dominates the others. Thus, thermal-aware workload allocation is more efficient. From the perspective of economic benefits, we propose a mathematical model for thermal distribution of a data center and study which workload distribution could determinately change the thermal distribution in the dynamic data center runtime, so as to reduce the cost and improve the economic benefits under the guarantee of service provisioning. By solving the thermal environment evaluation indexes, RHI and RTI, as well as heat dissipation models, we define quantitative models for the economic analysis such as energy consumption model for the busy servers and cooling, energy price model, and the profit model of data centers. Numerical simulation results validate our propositions and show that the average temperature of the data center reaches the best values, and the local hot spots are avoided effectively in various situations. As a conclusion, our studies contribute to the thermal management of the dynamic data center runtime for better economic benefits. (shrink)
On 19 October 2013, the Chinese government issued the Opinions on Further Regulation on Party and Political Leaders and Cadres Working Part-Time in Enterprises, also known (...) class='Hi'>as the 18th Decree, to regulate government officials’ employment with businesses. The 18th Decree is widely perceived as having had a significant impact on the use of independent directors with political backgrounds by firms, given the prevalence of this business practice. This paper examines the market reaction to the 18th Decree to ascertain the value effect of political connections in China. We note a negative relationship between the political connections of independent directors and market reaction. We also note that the negative relationship between political connections and market reaction is moderated by ownership type and state of regional development. Specifically, we find that the negative relationship holds only for private firms in less developed regions. These results support our prediction that political connections add value to Chinese firms and that the value effect of political connection is contingent on institutional factors. (shrink)
As an emerging film director, Yu Li has yet to be recognized by the international academic critics. By examining Hongyan/Dam Street in the Chinese cultural context (...) class='Hi'>with the assistance of analyzing scenes in detail and the film’s visual style, this article argues that the film illustrates the protagonist Xiaoyun is stuck between traditions and modernity, providing a sophisticated insight to an important feminist issue. The reading of the traditions involves chastity code, the image of a rouge face which is the translation of the film’s Chinese title, the Chinese four-character idioms, the time-honoured terms, the development of feminism, and the characteristics of the modernity in China. The perversity of the modernity originates from the social commercialization. Prejudices from the traditions and the modernity leave little space for women to settle in. (shrink)
Cities in the big data era hold the massive urban data to create valuable information and digitally enhanced services. Sources of urban data are generally categorized as (...) one of the three types: official, social, and sensorial, which are from the government and enterprises, social networks of citizens, and the sensor network. These types typically differ significantly from each other but are consolidated together for the smart urban services. Based on the sophisticated consolidation approaches, we argue that a new challenge, fragment complexity that represents a well-integrated data has appropriate but fragmentary schema and difficult to be queried, is ignored in the state-of-art urban data management. Comparing with predefined and rigid schema, fragmentary schema means a dataset contains millions of attributes but nonorthogonally distributed among tables, and of course, values of these attributes are even massive. As far as a query is concerned, locating where these attributes are being stored is the first encountered problem, while traditional value-based query optimization has no contributions. To address this problem, we propose an index on massive attributes as an attributes-oriented optimization, namely, attribute index. Attribute index is a secondary index for locating files in which the target attributes are stored. It contains three parts: ATree for searching keys, DTree for locating keys among files, and ADLinks as a mapping table between ATree and DTree. In this paper, the index architecture, logical structure and algorithms, the implementation details, the creation process, the integration to the existing key-value store, and the urban application scenario are described. Experiments show that, in comparison with B + -Tree, LSM-Tree, and AVL-Tree, the query time of ATree is 1.1x, 1.5x, and 1.2x faster, respectively. Finally, we integrate our proposition with HBase, namely, UrbanBase, whose query performance is 1.3x faster than the original HBase. (shrink)
In the context of China’s supply-side structural reform and the concept of green development, we introduce the energy and environmental factors into the analytical framework of (...) class='Hi'> the total factor productivity of the logistics industry and use the Global Malmquist–Luenberger index method to analyze the evolution trend and heterogeneity of green TFP in the logistics industry of 30 provinces in China from 2003 to 2017. The results show that, firstly, the green TFP and traditional TFP of China’s logistics industry are both on the rise and the absence of energy and environmental factors will lead to the overestimation of TFP of the logistics industry. Whether it is green TFP or traditional TFP, the main source of its growth is technical progress. Secondly, there is obvious regional heterogeneity in green TFP of logistics industry. Under the three regional division standards, the average annual growth rate of green TFP is from high to low in the order of eastern, western, and central regions. Under the eight regional classification standards, the eastern coastal economic zone, the southern coastal zone, the northern coastal zone, the northeast region, the middle reaches of the Yellow River, the southwest region, the middle reaches of the Yangtze River, and the northwest region are in order from high to low. Thirdly, there is obvious interprovincial heterogeneity in green TFP of the logistics industry. The highest growth rate of green TFP is in Zhejiang, followed by Jiangsu and Guangdong, and the slowest growth rate is in Chongqing. The technical progress of logistics industry in most provinces contributes more to the growth of green TFP. Fourthly, the differences of green TFP in the three regions of the east, center, and west are shrinking, which may be σ convergence, but the differences among the three regions are expanding. Compared with the existing literature, this paper applies the measurement framework of green TFP to China’s logistics industry and investigates the regional and provincial heterogeneity of green TFP in logistics industry. The conclusions are significant to understand and grasp the heterogeneity of green TFP growth in China’s logistics industry under environmental constraints and how to promote the development of green logistics in China. (shrink)
