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Construction industrialization is emerging in the construction industry, as a result, buildings with prefabricated assemblies are gaining more and more ground. In most situations, the prefabricated building assemblies are installed by labor crews manually. If some assemblies are ill-designed, clashes between labor crews’ workspaces and them may occur, which will have bad effect on workers’ productivity and even incur hazard. The purpose of this paper is to provide a 4D building information modeling (BIM) based approach to find potential workspace conflicts during the installation process of prefabricated building assemblies in the detailed design process so as to eliminate them in advance.

First, a workspace modeling method is provided; second, three kinds of workspace conflicts are analyzed; third, a 4D-BIM-based approach is established; fourth, a prototype tool based on the approach is developed; and finally, a case study is conducted to test the tool.

The result shows that the proposed tool can detect or precaution workspace conflicts and visualize them in a series of views; in doing so, valuable information can be obtained for improving the design quality of prefabricated assemblies.

The proposed approach and tool only concern the congestions caused by ill-designed prefabricated components; the tool needed to be further optimized for speed; the tests on the tool are limited to a single case study; and more tests are needed to verify its effectiveness.

This research provides a 4D-BIM-based approach and a prototype tool for installation workspace analysis. It can be used to provide support for design optimization of prefabricated building assemblies.

The purpose of this paper is to empirically analyze the transmission mechanism between benchmark interest rate of financial market, money market interest rate and capital market yields in order to reveal the dynamic evolution characters and core influential structure between different market interest rates.

Using Dirichlet-VAR (DVAR) model, this study analyze the relationship between markets rates according to the equilibrium model in money market and capital market.

Empirical results show that the interest rate transmission mechanism functions smoothly between interest rates of different levels. Interest rate of bills issued by the central bank can effectively reflect changes in monetary policy and guide the fluidity of market, playing the anchor role in interest rate pricing. There exists a closed loop feedback between interest rate of bills issued by the central bank, and money market interest rate, as well as between money market interest rate and bond market interest rate. The former is a loop by administrative means while the latter is the one mainly affected by market-oriented means. The response by money market and bond market toward the change of benchmark interest rate is unsymmetrical as money market is more sensitive to a loose monetary policy while bond market is more sensitive to a tight monetary policy. Stock market is strongly affected by uncertainty of benchmark interest rate.

DVAR model is the extension of research on instable data and multiple variable causality test, which expands the causality analysis between two variables to multiple variables causality impact analysis which contains non-stable and structurally instable economic data.

The purpose of this paper is to find the root cause of the current issue for a scan drive mechanism which is used to drive and to control the Microwave Radiometer Imager (MWRI) equipment of the FY‐3 meteorological satellite in China.

In order to find the root cause of the irregularly unstable motor current, some possible reasons for this anomaly, including satellite dynamic, telemetry, electronics and mechanism system, are investigated. The root cause is focused on the mechanism that is increasing friction caused by limitation rollers striking the rotating part from time to time, which has been verified by simulation and test.

Findings gained from the simulations and tests results were: for a rotational space mechanism with high velocity accuracy requirement, if the moment of inertial (MOI) of the load is quite large, the balance is the key factor to the equipment performance. Moreover, thermal gradient and temperature difference are also important factors, especially to the space mechanism with large dimensions. Even a very small thermal deformation can lead to quite a number of unexpected results.

The better performance of the next optimized MWRI equipment in orbit showed that the performed measures are very effective and useful. The experience gained in settling this issue can be used for the design of a space scanning mechanism with high rotating speed and high accuracy.

The paper is an original work for the authors. The issue has not been found in the related literatures. It is based on research work on an engineering problem of unstable current issue, which is significant to the MWRI payload of the FY‐3 satellite.

The “Snap back” problem of the micro‐cantilever remains one of the dominant failure mechanisms in the Micro Electro‐mechanical System (MEMS). By analyzing the Hamaker micro continuum medium and solid physics principle, the consistency model of Wigner‐Seitz (W‐S) continuum medium is presented. The gap revision coefficients of the body with the face‐centered cubic structure are derived, which include the attractive force and the repulsive one. The adhesion model of the 500 µ m X 1 µ m silicon micro‐cantilever coated by Au is established. The micro‐cantilever static relationship between the elastic force and the adhesion force is discussed. The reason of the microcantilever “snap back” problem, an instable balanced point, is discovered. Increasing the rigidity of the micro‐cantilever, a method to avoid the micro‐cantilever “snap back” to happen, is put forward, which improves MEMS structure design and enhances MEMS reliability.

The purpose of this paper is to examine the nature and extent of instability of capital asset pricing model (CAPM) beta in a small emerging capital market.

Inter‐period as well as intra beta instability are examined. Inter‐period instability is examined by Mann‐Whitney z‐scores and Blume's regressions. Intra‐period beta instability is examined using Bruesch‐Pagan LM test and Chow break point test. Robustness tests are performed applying time‐varying parameter models.

Beta instability increases with increase in holding (sample) periods. There is evidence of inter‐period as well as intra‐period beta instability. Analysis of the full eight‐year interval reveals a very high incidence of beta instability, namely, about 26 per cent of the individual stocks tested and about 31 per cent of individual stocks have structural break. The extent of beta instability does not significantly decline when corrected for non‐synchronous trading and thin trading as represented by Dimson beta. However, the extent of beta instability is similar to that of developed market. Time‐varying parameter model under Kalman filter approach using AR(1) specification performs better than any other models in terms of in‐sample forecast errors. Dominance of AR(1) approach suggests that stock betas in DSE are time varying, and shocks to the conditional beta have some degree of persistence which ultimately reverts to a mean. This result is in contrast to the findings of Faff et al. revealing the dominance of Random Walk specification in Australian market, suggesting that shocks to stock beta in Australian market persist indefinitely into the future. These contrasting findings may indicate that beta instability in different markets and for different stocks in the same market are of different nature and different models may be suitable for different markets and different stocks in the same market in capturing the time‐varying nature of beta coefficients.

This study covers only 110 stocks of Dhaka Stock Exchange. It can be extended to include more stocks. The study can also be done in other developing markets.

While the issues of beta instability have been extensively explored for developed markets, evidence for emerging markets is less readily available. The present study contributes to the emerging market literature on beta instability by investigating the extent of beta instability and its time‐varying properties in Dhaka Stock Exchange (DSE), Bangladesh. Understanding the systematic risk behaviour of individual stocks in DSE is important for both local and international investors. With the saturation of investment opportunities in developed markets due to their high integration, and with the enhanced deregulation and liberalization of emerging economies, emerging financial markets like DSE provide suitable and a relatively safe investment environment for international investors and fund managers seeking global diversification for better risk‐return trade‐offs. When most of the world markets declined during the recent global financial crisis, stock prices in DSE experienced a continuous rise. This makes it more interesting as an emerging market to study beta instability.

The purpose of this paper is to develop an effective numerical approach to assess the nonlinear dynamic responses of a near‐bed submarine pipeline.

A coupled numerical approach is proposed in this paper to assess the nonlinear dynamic responses of this pipeline. The boundary‐element method is first used to get the nonlinear dynamic fluid loading induced by the asymmetric flow. The meshless technique is used to discretize the structure of the pipeline. A numerical example is first presented to verify the effectivity of the present method. Then, the coupled technique is used to simulate the nonlinear dynamic fluid‐structure interaction problem of a near‐bed pipeline. A Newton‐Raphson iteration procedure is used herein to solve the nonlinear system of equations, and the Newmark method is adopted for the time integration.

The presence of seabed results in a large negative lift on a pipeline in a horizontal current. Studies reveal that there exists a critical current velocity, above which the pipeline will become instable, and the critical velocity is significantly affected by the initial gap from the pipeline to the seabed.

The near‐bed submarine pipeline is a widely used structure in marine engineering. This paper originally develops a numerical approach to model this special fluid‐structure interaction problem. It has demonstrated by the examples that the present approach is very effective and has good potential in the practical applications.

The purpose of this paper is to review the theoretical background, methodological extensions, and empirical applications of the Engel curve, which is applied to the research of the change in farmers’ welfare and food demand in China after the economic reform in 1978, compared with the statistics of income and food consumption.

This paper mainly uses the traditional method of Engel curve, which is compared with income growth and food consumption, to study farmers’ welfare improvement in rural China.

The Engel coefficients identify three different stages for farmers’ welfare change after 1978. The first stage is the period between 1978 and 1988, in which farmers’ welfare has been continuously enhanced due to the institutional bonus of the 1978 economic reform and increased government purchase price of agricultural products. The second stage is the period between 1989 and 1995, in which farmers’ welfare has been slightly deteriorated mainly due to the end of institutional reform bonus, suppressed food prices, relative high inflation, and instable political situation. The third stage is the period after 1995, in which farmers’ welfare returns to a growing path, as the dual price system was abolished, the transition from a planned economy to a market economy had been completed, and the government carried out protective policies for agriculture and started to heavily subsidize agriculture. The Engel coefficient still remained at a very high level at 0.59 in 1995, but it continuously decreased to 0.33 in 2015. The welfare enhancement for farmers mainly results from deepened market-oriented reform, protective policies for agriculture, and prevalent off-farm employment. The Engel coefficient is also linked to food demand elasticities. Along with the decreasing Engel coefficient in the past 40 years, income elasticities also continuously decrease from 0.55 in 1978 to 0.08 in 2015. Food demand is very inelastic now, and any further increase in income will not substantially increase food demand any more.

Inequality has not been analyzed.

This paper reviews the methodological advantages of the Engel curves, and uses it to identify different stages of welfare change and estimate income elasticities of food demand for farmers in China after the 1978 economic reform.

The purpose of this paper is to propose a control approach for small unmanned helicopters, and a novel swarm intelligence algorithm is used to optimize the parameters of the proposed controller.

Small unmanned helicopters have many advantages over other unmanned aerial vehicles. However, the manual operation process is difficult because the model is always instable and coupling. In this paper, a novel optimized active disturbance rejection control (ADRC) approach is presented for small unmanned helicopters. First, a linear attitude model is built in hovering condition according to small perturbation linearization. To realize decoupling, this model is divided into two parts, and each part is equipped with an ADRC controller. Finally, a novel Levy flight-based pigeon-inspired optimization (LFPIO) algorithm is developed to find the optimal ADRC parameters and enhance the performance of controller.

This paper applies ADRC method to the attitude control of small unmanned helicopters so that it can be implemented in practical flight under complex environments. Besides, a novel LFPIO algorithm is proposed to optimize the parameters of ADRC and is proved to be more efficient than other homogenous methods.

The model of proposed controller is built in the hovering action, whereas it cannot be used in other flight modes.

The optimized ADRC method can be implemented in actual flight, and the proposed LFPIO algorithm can be developed in other practical optimization problems.

ADRC method can enhance the response and robustness of unmanned helicopters which make it valuable in actual environments. The proposed LFPIO algorithm is proved to be an effective swarm intelligence optimizer, and it is convenient and valuable to apply it in other optimized systems.

Many cities implement freight traffic restriction policy (FTRP) intending to reduce traffic congestion and air pollution. At the same time, city distribution had some negative effects. The purpose of this paper is therefore to study the freight group behavior under FTRP, and to provide some recommendations for the government.

This paper establishes a city distribution system model built by a simulation method of Agent, which includes the complex adaptability of freight individual, event of restriction policy, the influence factor of freight group behavior and its changes from the perspective of restriction policy. The rules of microscopic freight group behavior to macroscopic freight group behavior, the effects on freight group behavior exerted by restriction policy and the dynamic mechanism of freight group behavior are all studied. The model is also simulated with the traffic data of Beijing in China.

Theoretical results ensure that restriction of the passport is not the sole reason that may produce illegal trucks, and other measures need to be taken to solve the traffic problems. And in the long run, increasing fines has a greater effect than strengthening supervision frequency on illegal trucks reduction.

From city distribution perspective, this paper studied freight group behavior under FTRP. This paper also applied the Agent modeling method to build a model of urban distribution system in the FTRP.

The paper explores the precarious balance between modernizing monetary systems by means of digital currencies (either issued by the central bank itself or independently) and safeguarding financial stability as also ensured by tangible payment (and saving) instruments like paper money.

Which aspects of modern payment systems could contribute to improve the way of functioning of today's globalized economy? And, which might even threaten the above-mentioned instable equilibrium? This survey paper aims, precisely, at giving some preliminary answers to a complex – therefore, ongoing – debate at scientific as well as banking and political levels.

The coexistence of State's money (i.e. “legal tender”) and cryptocurrencies can have a disciplining effect on central banks. Nevertheless, there are still high risks connected to the introduction of central bank digital currency, which should be by far not considered to be a perfect substitute of current cash. At the same time, cryptocurrencies issued by central banks might be exposed to the drawbacks of cryptocurrencies without benefiting from correspondingly strong advantages. A well-governed two-tier system to be achieved through innovation in payment infrastructures might be, in turn, more preferable. Regulated competition by new players combined with “traditional” deposits and central bank elements remains essential, although central banks should embrace the technologies underlying cryptocurrencies, because risk payment service providers could move to other currency areas considered to be more appealing for buyers and sellers.

We do not see specific limitations besides the fact that the following is for sure a broad field of scientific research to be covered, which is at the same time at the origin of ongoing developments and findings. Originality and implications of the paper are, instead, not only represented by its conclusions (which highlight the role of traditional payment instruments and stress why the concept of “money” still has to have specific features) but also by its approach of recent literature's review combined with equally strong logical-analytical insights.

In the light of these considerations, even the role of traditional payment systems like paper money is by far not outdated or cannot be – at this point, at least – replaced by central bank digital currencies (whose features based on dematerialization despite being issued and guaranteed by a public authority are very different).

No matter which form it might assume is what differentiates economic from barter transactions. This conclusion is by far not tautological or self-evident since the notion of money has historically been a great object of scientific discussion. In the light of increasingly modern payment instruments, there is no question that money and the effectiveness of related monetary policies have to be also explored from a social perspective according to different monetary scenarios, ranging from central bank digital currencies to private currencies and cash restrictions/abolition.

The originality/value of the following article is represented by the fact that it (1) refers to some of the most relevant and recent contributions to this research field, (2) moves from payment systems in general to their newest trends like cryptocurrencies, cash restrictions (or, even, abolition proposals) and monetary policy while (3) combining all elements to reach a common picture. The paper aims at being a comprehensive contribution dealing with "money" in its broadest but also newest sense.