The company you keep: How network disciplinary diversity enhances the productivity of researchers

The Covid-19 pandemic has affected most organizations' working environment and productivity. Organizations have had to make provision for staff to operate remotely following the implementation of lockdown regulations around the world, because the pandemic has led to restrictions on movement and the temporary closure of workplace premises. The purpose of this paper is to gain a deeper understanding of the effect of this transition on the productivity of work during the pandemic, by studying a distributed network of research who collaborate remotely. We examine how the productivity of researchers is affected by the distributed collaborative networks in which they are embedded. Our goal is to understand the effects of brokerage and closure on the researchers’ publication rate, which is interpreted as an indicator of their productivity. We analyze researchers’ communication networks, focusing on structural holes and diversity, and we take into account the personal qualities of the focal researcher such as seniority. We find that disciplinary diversity among researchers' peers' increases the researchers’ productivity, lending support to the brokerage argument. In addition, we find support for two statistical interaction effects. First, structural holes moderate diversity so that researchers with diverse networks are more productive when their networks also have a less redundant structure. Diversity and structural holes, when combined, further researchers’ productivity. Second, seniority moderates diversity; so that senior researchers are more productive than junior researchers in less diverse networks. In more diverse networks, junior researchers perform as well as senior researchers. Social capital and human capital are complementary. We conclude that the benefits of diversity on researchers’ productivity are contingent on the personal qualities of the researchers and on network structure. The brokerage / closure debate needs a more nuanced understanding of causal relationships.

Condition-based opportunistic maintenance policy for a series–parallel hybrid system with economic dependence

PurposeThe purpose of this paper is to propose a condition-based opportunistic maintenance policy considering economic dependence for a series–parallel hybrid system with a K-out-of-N redundant structure, where a single component in series is denoted as subsystem1, and K-out-of-N redundant structure is denoted as subsystem2.Design/methodology/approachBased on the theory of Residual Useful Life (RUL), inspection points are determined, and then different maintenance actions are adopted in the purpose of minimizing the cost rate. Both perfect and imperfect maintenance actions are carried out for subsystem1. More significantly, regarding economic dependence, condition-based opportunistic maintenance is designed for the series–parallel hybrid system: preemptive maintenance for subsystem1, and both preemptive and postponed maintenance for subsystem2.FindingsThe sensitivity analysis indicates that the proposed policy outperforms two classical maintenance policies, incurring the lowest total cost rate under the context of both heterogeneous and quasi-homogeneous K-out-of-N subsystems.Practical implicationsThis model can be applied in series–parallel systems with redundant structures that are widely used in power transmission systems in electric power plants, manufacturing systems in textile factories and sewerage systems. Considering inconvenience and high cost incurred in the inspection of hybrid systems, this model helps production managers better maintain these systems.Originality/valueIn maintenance literature, much attention has been received in repairing strategies on hybrid systems with economic dependence considering preemptive maintenance. Limited work has considered postponed maintenance. However, this paper uses both condition-based preemptive and postponed maintenance on the issue of economic dependence bringing opportunities for grouping maintenance activities for a series–parallel hybrid system.

Methodological Support for Applying the Method of Majority Reservation in Measuring Channels

Introduction. For hazardous industries, the reliability of information and measuring equipment must ensure an almost complete absence of failure events, with their probability as low as 10-6. This requirement can be satisfied using various approaches, one of which is reservation. Reservation methods are classified into several types depending on such factors, as the operating mode of an object, failure types, frequency rate, etc. Majority redundancy schemes are rarely used in measuring equipment, particularly in measuring channels, largely because this method was initially aimed at improving the reliability of discrete digital devices. Thus far, no mathematical support for applying the method of majority reservation in measuring channels of analogue values has been developed. This gap determined the relevance of this study.Aim. To develop a methodological support for applying the method of majority reservation with the purpose of improving the level of measurement accuracy.Materials and methods. Both Russian and foreign sources published over the past 40 years on the topic of processing small samples when designing measuring channels for information and measuring systems were reviewed. The nonparametric Mann-Whitney rank test was applied to process small samples. Other research methods included mathematical modelling, as well as the mathematical apparatus of measurement theory andтsystems theory.Results. A measuring module with a redundant structure was simulated. Parametric and nonparametric rank criteria were considered. An algorithm allowing identification of the failure of a channel in a measuring module with a redundant structure was developed. The computational complexity of the developed algorithm is estimated by a polynomial of the second degree.Conclusion. The use of nonparametric rank criteria for processing small samples, as well as diagnostic situations for various combinations of these criteria, supports statistically grounded decision on the state of measuring channels. In the future, this method will be applied for diagnostic control of the serviceability of technological equipment used in fuel combustion, namely in boiler plants and installations for thermal waste destruction.

A QUAD CMOS GATES CHECKING METHOD

The so-called Fault-Tolerant Systems (FTS) use the structural, temporal, functional, or information redundancy for the achievement of the high reliability. For example, Radiation Hardened by Design (RHBD) Systems are Fault-Tolerant Systems. A Passive FTS, due to a very large structural redundancy (Modular Redundancy), produces faults masking. The Triple Modular Redundancy (TMR) Method has more than 300% redundancy. The Quad Redundancy (QR) Method boasts more than 400% redundancy. The CMOS transistors QR (transistor-level redundancy) is the most effective QR. In this case, no voting element is needed. However, this significantly increases the time delay. In addition, it is necessary to ensure compliance with the Mead-Conway restrictions. QR, in contrast to TMR, raises the problem of checking the redundant structure. The author proposes a QR Checking Method based on a selection of substrates of the CMOS transistors. The power lines of the transistor substrates are separated, which ensures the disconnection of part of the reserve. A simulation confirms the feasibility of the proposed method.

Simulation Assessment of the Performance of a Redundant SCARA

The present paper analyses the potential dynamic performance of a novel redundant SCARA robot, currently at the stage of a functional design proposed by a renowned robot manufacturer. The static and dynamic manipulability of the new concept is compared with the conventional model of the same manufacturer by means of computer simulation in typical pick and place tasks arising from industry. The introduction of a further revolute joint in the SCARA robot kinematics leads to some improvements in the kinematic and dynamic behaviour at the expense of a greater complexity. In this paper, the potential of a redundant SCARA architecture in cutting cycle-times is investigated for the first time in performing several tasks. It is shown that, in order to exploit the possible enhancements of the redundant structure, the whole manipulator, mechanics and control must be redesigned according to specific tasks aiming at the optimization of their cycle-time.