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This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration.

A modified dynamic movement primitives (DMPs) model with a novel hybrid force/position feedback in Cartesian space for the robotic PiH problem is proposed by learning from demonstration. To ensure a compliant interaction during the PiH insertion process, a Cartesian impedance control approach is used to track the trajectory generated by the modified DMPs.

The modified DMPs allow the robot to imitate the trajectory of demonstration efficiently and to generate a smoother trajectory. By taking advantage of force feedback, the robot shows compliant behavior and could adjust its pose actively to avoid a jam. This feedback mechanism significantly improves the dynamic performance of the interactive process. Both the simulation and the PiH experimental results show the feasibility and effectiveness of the proposed model.

The trajectory and the compliant manipulation skill of the human operator can be learned simultaneously by the new model. This method adopted a modified DMPs model in Cartesian space to generate a trajectory with a lower speed at the beginning of the motion, which can reduce the magnitude of the contact force.

The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.

A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP.

Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy.

Because of the chosen research approach, the research results may need to be tested by further experiments.

The paper includes implications for the optimization of smoke control systems design in buildings.

This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.

The purpose of this paper is to investigate the tribological properties of MoS₂ nano‐sized hollow spheres in liquid paraffin (LP) and the corresponding action mechanism. Morever, its feasibity of industrial application as an oil additive in the industrial lubrication field is also explored.

The tribological properties of MoS₂ nano‐sized hollow spheres (NH‐MoS₂) modified by Cyanex 301(di‐(2,4,4‐trimethylpentyl) dithiophosphinic acid) with size of 200 ∼ 300 nm in LP are studied and compared with those of the commercial colloidal MoS₂ (CC‐MoS₂) on a four‐ball tester and an Optimol SRV Oscillating friction and wear tester in a ball‐on disk configuration. The worn surfaces of the lower flat disc are examined with a scanning electron microscopy and an X‐ray photoelectron spectroscopy, respectively.

Results show that NH‐MoS₂ is a better extreme‐pressure additive and anti‐wear (AW) and friction‐reducing additive in LP than CC‐MoS₂. Under the optimum concentration of 0.5 per cent for both NH‐MoS₂ and CC‐MoS₂ and the load of 400 N, the friction coefficient of NH‐MoS₂ + LP and CC‐MoS₂ + LP decreases about 43.8 and 6.3 per cent, and the wear volume loss decreases about 60.3 and 12.0 per cent compared with the pure LP. The boundary lubrication mechanism for NH‐MoS₂ + LP can be deduced as the effective chemical adsorption protective film formed by the long chain alkyls R and active elements (S and P) in the modification layer and tribochemical reaction film containing the tribochemical products of the additive. Moreover, sliding and rolling frictions co‐exist in NH‐MoS₂ + LP, doing contributions to the good tribological properties as well.

In this paper, the Cyanex 301‐modified MoS₂ nano‐sized hollow spheres with diameter of 200 ∼ 300 nm are firstly added into LP to investigate its tribological properties. The excellent AW and friction‐reducing properties indicate that this MoS₂ hollow spheres product is a good oil additive, and the fundamental data presented here will be useful for its further industrial application in the future.

The purpose of this paper is to study the behavior of smoke flow in a typical high-rise residential building fire in six common smoke control systems.

The pressure, temperature and CO₂ concentration were used to trace the motion of turbulent smoke flow through CFD.

It is found that the hot smoke could rise up and spread into the indoor space on the upper floors through the staircase. When the pressure in the evacuation staircase is higher, it would be more difficult for the smoke to enter the staircase and transport vertically. On the other hand, the smoke would soon transport to the indoor space on the upper floors horizontally. During this process, the smoke shows a more disorder horizontal transport under the sole effect of thermal buoyancy than the co-existence of thermal buoyancy and the air inlet.

Because of the chosen research approach, the research results may need to be tested by further experiments.

The paper includes implications for the design of smoke control systems and evacuation in a building fire.

This paper fulfils an identified need to study the behavior of smoke in a fire and optimize the design of smoke control systems.

The purpose of this study is to use role expectation theory to identify potential determinants of user voting avoidance on mobile social media.

Data were collected through a survey of 602 WeChat users, and the proposed model was analysed using structural equation modelling.

Results indicate that user voting avoidance was positively influenced by unfair competition, perceived inauthenticity, perceived information insecurity, over-consumption of renqing (a unique Chinese human relation) and organisation placement in the context of mobile social media.

This study illustrates mobile user voting avoidance from the perspective of role expectation theory and clarifies the importance of avoidance in current voting research.

This study aims to examine if the participation of live-stream influencers (LSIs) affects tipping frequency on live streaming platforms, and further investigate the mediating and moderating mechanisms.

Quasi-experiment and difference-in-differences models are used for data analysis. Propensity score matching is used to address potential unobservable endogeneity.

Real-time live streaming data reveal that LSIs’ participation significantly improves tipping frequency in live streaming rooms. Also, more users are attracted to the live streaming rooms and more users become active in participation. Additionally, the positive impact of LSIs’ participation is enhanced in the live streaming rooms with a greater number of relationship links between users.

The findings clarify the new role of influencers and reveal the mechanisms on how LSIs benefit the platforms.

The findings offer novel insights into implementing influencer marketing to interactive social media platforms, by encouraging influencer participation, user relationship building and influencer network growth.

This study highlights the value of LSIs for interactive social media platforms in terms of organic growth, revenue generation and cost reduction.

The purpose of this paper is to empirically investigate the effects of competence and goodwill trust on knowledge creation and the moderating effects of legal inadequacy on those relationships.

A questionnaire survey was used to collect data from 196 research and development alliances in China. Hierarchical moderated regression was used to test the research hypotheses.

The authors find that competence trust has a positive and linear relationship with knowledge creation while goodwill trust has an inverted U-shaped relationship with it. The results also reveal that the inverted U-shaped relationship between goodwill trust and knowledge creation is stronger when legal inadequacy is high, while the impact of competence trust on knowledge creation is not influenced by legal inadequacy.

The findings provide insights into the distinctive effects of competence and goodwill trust on knowledge creation in partnerships, deepening current understandings of the bright and dark sides of inter-firm trust. This study also clarifies the influences of legal inadequacy on the effectiveness of competence and goodwill trust, which enhances existing knowledge about the impact of legal systems on the relationships between inter-firm trust and knowledge management.

Inductance, torque and iron loss are the key parameters of switched reluctance motors for belt-driven starter generators. This paper aims to present the analysis of a segmented rotor switched reluctance motor (SSRM) with three types of winding connections for hybrid electric vehicle applications by using a two-dimensional finite element method.

The rotor of the studied SSRM consists of a series of discrete segments, while the stator is made up of exciting and auxiliary teeth. First, the concept and structures of the different winding connections are introduced. Then, the magnetic flux path of the three types of winding connections for the SSRM is described. Second, the magnetic flux distributions in the three parts, i.e. the stator yoke, the stator tooth and the rotor segment, are described in detail to calculate the iron losses. Third, three SSRMs with the different winding arrangements are analyzed and compared to evaluate the distinct features of the studied SSRM. The analysis and comparison mainly include self-inductances, mutual inductances, phase currents, output torque and iron loss.

It is found that the self-inductances of the three types of winding connections are almost equal, and only the SSRM1 has a positive mutual inductance. In addition, the current waveforms of SSRM1 and SSRM2 are regular. However, it is irregular in SSRM3. It is shown that SSRM1 has better characteristics, such as higher output torque, high power density, lower torque ripple and iron loss.

This paper proposes and analyzes three novel winding connections for the SSRM to provide guidance for enhancing the output torque and reducing the iron loss to achieve high efficiency.

The purpose of this paper is to empirically investigate the effects of cooperation history on contractual governance and the moderating effects of dependence asymmetry on those relationships from the perspective of a weaker firm in emergent economies. Drawing from resource dependence theory and contingency theory, this paper develops a conceptual model to investigate the impact of cooperation history on contractual governance.

The authors use data from 188 buyer–supplier relationships in China

The authors find that cooperation history is positively associated with contractual governance when dependence asymmetry is high but negatively associated with contractual governance when dependence asymmetry is low. Furthermore, the negative moderating effect of dependence asymmetry on the relationship between cooperation history and contractual complexity is stronger than the relationship between cooperation history and contract enforcement.

This study contributes to a better understanding of how cooperation history affects contractual governance with respect to the various levels of dependence on partners by incorporating a contingency view. This study also advances the literature on interfirm governance by distinguishing contractual governance into contractual complexity and contract enforcement.

Users often struggle to select choosing among similar online services. To help them make informed decisions, it is important to establish a service reputation measurement mechanism. User-provided feedback ratings serve as a primary source of information for this mechanism, and ensuring the credibility of user feedback is crucial for a reliable reputation measurement. Most of the previous studies use passive detection to identify false feedback without creating incentives for honest reporting. Therefore, this study aims to develop a reputation measure for online services that can provide incentives for users to report honestly.

In this paper, the authors present a method that uses a peer prediction mechanism to evaluate user credibility, which evaluates users’ credibility with their reports by applying the strictly proper scoring rule. Considering the heterogeneity among users, the authors measure user similarity, identify similar users as peers to assess credibility and calculate service reputation using an improved expectation-maximization algorithm based on user credibility.

Theoretical analysis and experimental results verify that the proposed method motivates truthful reporting, effectively identifies malicious users and achieves high service rating accuracy.

The proposed method has significant practical value in evaluating the authenticity of user feedback and promoting honest reporting.