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A routine numerical method of solving integral equations arising in steady supersonic flow past flexible delta wings, with supersonic and subsonic leading edges, is presented. The wing is subdivided into diamond shaped panels, by a network of equi‐spaced Mach lines, and the effect of placing unit downwash at each panel in turn is calculated. The resulting influence function, which has been tabulated, is then formed into the required matrix of influence coefficients. Within the limitations of linearized theory the results are valid for all Mach numbers and mode shapes, including chordwise bending. Although applied here to delta wings the method is equally suited to wings of arbitrary plan form. An aeroelastic efficiency calculation, for a sonic leading edge 45 deg. delta wing of representative torsional stiffness, is included for comparison with strip theory.

Work crew productivity and the application of limited resources are necessary elements in construction duration delay analysis. This study thus proposes a method to analyze construction delays and resource reallocation based on work crew productivity and resource constraints. The study also presents an economic feasibility analysis that maximizes economic effect by reducing construction duration, the cost of resource reallocation, delay liquidated damages (DLDs) and incentives for reducing contractual duration.

The proposed method involved three steps. First, work crew characteristics such as productivity, unit price and workload helped analyze delay information, including delay duration, reducible duration and daily reduced cost. Next, a goal programming method assessed resource reallocation based on the priority (as determined by decision-makers) of each constraint condition, such as the available number of workers, cost, goal workload and statutory working hours. Lastly, the level of reallocation was analyzed based on the results of the economic feasibility analysis and decision-makers’ delay attitudes.

A case study was performed to test the proposed method's applicability. Its involved sensitivity analysis indicated proposing to decision-makers a scenario based on the prioritization of economic feasibility. The proposed method's applicability proved high for decision-makers, as they can determine whether to reduce construction duration per the proposed data.

The proposed method's main contribution is the reallocation of resources to reduce construction duration based on work crew productivity and the prioritization of limited resources. The proposed method can analyze the differences in productivity between the plan and actual progress, as well as calculate the necessary number of workers. Decision-makers can then reduce the appropriate level of contractual duration based on their own delay attitude, constraint condition prioritization and results from daily economic feasibility analyses.

Voltage source inverter-fed permanent magnet synchronous motors (VSI-PMSMs) are widely used in industrial actuation and mechatronic systems in water pumping stations, as well as in the traction of transportation systems (such as electric vehicles and electric trains or ships with electric propulsion). The dynamic model of VSI-PMSMs is multivariable and exhibits complicated nonlinear dynamics. The inverters’ currents, which are generated through a pulsewidth modulation process, are used to control the stator currents of the PMSM, which in turn control the rotational speed of this electric machine. So far, several nonlinear control schemes for VSI-PMSMs have been developed, having as primary objectives the precise tracking of setpoints by the system’s state variables and robustness to parametric changes or external perturbations. However, little has been done for the solution of the associated nonlinear optimal control problem. The purpose of this study/paper is to provide a novel nonlinear optimal control method for VSI-fed three-phase PMSMs.

The present article proposes a nonlinear optimal control approach for VSI-PMSMs. The nonlinear dynamic model of VSI-PMSMs undergoes approximate linearization around a temporary operating point, which is recomputed at each iteration of the control method. This temporary operating point is defined by the present value of the voltage source inverter-fed PMSM state vector and by the last sampled value of the motor’s control input vector. The linearization relies on Taylor series expansion and the calculation of the system’s Jacobian matrices. For the approximately linearized model of the voltage source inverter-fed PMSM, an H-infinity feedback controller is designed. For the computation of the controller’s feedback gains, an algebraic Riccati equation is iteratively solved at each time-step of the control method. The global asymptotic stability properties of the control method are proven through Lyapunov analysis. Finally, to implement state estimation-based control for this system, the H-infinity Kalman filter is proposed as a state observer. The proposed control method achieves fast and accurate tracking of the reference setpoints of the VSI-fed PMSM under moderate variations of the control inputs.

The proposed H-infinity controller provides the solution to the optimal control problem for the VSI-PMSM system under model uncertainty and external perturbations. Actually, this controller represents a min–max differential game taking place between the control inputs, which try to minimize a cost function that contains a quadratic term of the state vector’s tracking error, the model uncertainty, and exogenous disturbance terms, which try to maximize this cost function. To select the feedback gains of the stabilizing feedback controller, an algebraic Riccati equation is repetitively solved at each time-step of the control algorithm. To analyze the stability properties of the control scheme, the Lyapunov method is used. It is proven that the VSI-PMSM loop has the H-infinity tracking performance property, which signifies robustness against model uncertainty and disturbances. Moreover, under moderate conditions, the global asymptotic stability properties of this control scheme are proven. The proposed control method achieves fast tracking of reference setpoints by the VSI-PMSM state variables, while keeping also moderate the variations of the control inputs. The latter property indicates that energy consumption by the VSI-PMSM control loop can be minimized.

The proposed nonlinear optimal control method for the VSI-PMSM system exhibits several advantages: Comparing to global linearization-based control methods, such as Lie algebra-based control or differential flatness theory-based control, the nonlinear optimal control scheme avoids complicated state variable transformations (diffeomorphisms). Besides, its control inputs are applied directly to the initial nonlinear model of the VSI-PMSM system, and thus inverse transformations and the related singularity problems are also avoided. Compared with backstepping control, the nonlinear optimal control scheme does not require the state-space description of the controlled system to be found in the triangular (backstepping integral) form. Compared with sliding-mode control, there is no need to define in an often intuitive manner the sliding surfaces of the controlled system. Finally, compared with local model-based control, the article’s nonlinear optimal control method avoids linearization around multiple operating points and does not need the solution of multiple Riccati equations or LMIs. As a result of this, the nonlinear optimal control method requires less computational effort.

Voltage source inverter-fed permanent magnet synchronous motors (VSI-PMSMs) are widely used in industrial actuation and mechatronic systems in water pumping stations, as well as in the traction of transportation systems (such as electric vehicles and electric trains or ships with electric propulsion), The solution of the associated nonlinear control problem enables reliable and precise functioning of VSI-fd PMSMs. This in turn has a positive impact in all related industrial applications and in tasks of electric traction and propulsion where VSI-fed PMSMs are used. It is particularly important for electric transportation systems and for the wide use of electric vehicles as expected by green policies which aim at deploying electromotion and at achieving the Net Zero objective.

Unlike past approaches, in the new nonlinear optimal control method, linearization is performed around a temporary operating point, which is defined by the present value of the system’s state vector and by the last sampled value of the control input vector and not at points that belong to the desirable trajectory (setpoints). Besides, the Riccati equation, which is used for computing the feedback gains of the controller, is new, as is the global stability proof for this control method. Comparing with nonlinear model predictive control, which is a popular approach for treating the optimal control problem in industry, the new nonlinear optimal (H-infinity) control scheme is of proven global stability, and the convergence of its iterative search for the optimum does not depend on initial conditions and trials with multiple sets of controller parameters. It is also noteworthy that the nonlinear optimal control method is applicable to a wider class of dynamical systems than approaches based on the solution of state-dependent Riccati equations (SDRE). The SDRE approaches can be applied only to dynamical systems that can be transformed to the linear parameter varying form. Besides, the nonlinear optimal control method performs better than nonlinear optimal control schemes which use approximation of the solution of the Hamilton–Jacobi–Bellman equation by Galerkin series expansions.

The purpose of this paper is to collect and understand the nature of real cases of author name variants that have often appeared in bibliographic digital libraries (DLs) as a case study of the name authority control problem in DLs.

To find a sample of name variants across DLs (e.g. DBLP and ACM) and in a single DL (e.g. ACM), the approach is based on two bipartite matching algorithms: Maximum Weighted Bipartite Matching and Maximum Cardinality Bipartite Matching.

First, the authors validated the effectiveness and efficiency of the bipartite matching algorithms. The authors also studied the nature of real cases of author name variants that had been found across DLs (e.g. ACM, CiteSeer and DBLP) and in a single DL.

To the best of the authors knowledge, there is less research effort to understand the nature of author name variants shown in DLs. A thorough analysis can help focus research effort on real problems that arise when the authors perform duplicate detection methods.

Governments across the globe appear to identify and tout technology as a way to transform how they govern. Public procurement is at the forefront of most reform efforts given that it plays a significant role in promoting accountability and transparency. This study relies on survey data of procurement professionals to delineate the current status of eprocurement implementation in United States and Canada. Findings suggest that digitalized public procurement has not yet led to significant transformative changes. Unsuitability of software platforms, organizational resistance, lack of strategic systemsʼ integration and failure to involve public procurement professionals in the design of e-procurement systems were identified as the primary obstacles of effectively implementing digital procurement. These findings suggest that in order to capitalize on the potentially transformative nature of ICT in procurement, policymakers, system designers, and procurement professionals must take an active role in both the design of the software and its adoption across political, institutional and behavioral domains.

The dynamics of the PV microgrid (PVMG) system are highly nonlinear and uncertain in nature. It is encountered with parametric uncertainties and disturbances. This system cannot be controlled properly by conventional linear controllers. H⁻ controller and sliding mode controller (SMC) may capable of controlling it with ease. Due to its inherent dynamics, SMC introduces unwanted chattering into the system output waveforms. This paper aims to propose a controller to reduce this chattering.

This paper presents redesign of the SMC by modifying its sliding surface and tuning its parameters by employing water-evaporation-optimization (WEO) based metaheuristic algorithm.

By using this proposed water-evaporation-optimization algorithm-double integral sliding mode controller (WEOA-DISMC), the chattering magnitude is diminished greatly. Further, to examine which controller between H8 controller and proposed WEOA-DISMC performs better in both normal and uncertain situations, a comparative analysis has been made in this paper. The considered comparison parameters are reference tracking, disturbance rejection and robust stability.

WEO tuned DISMC for PVMG system is the contribution.

ESTIMATE time, which is now, is always a time of thought for the librarian. Budgets this year show no general sign of important change, because the country is working in an atmosphere of war‐time prosperity. Economists of the orthodox school advise us that this is temporary and artificial. Possibly so, although they seem to omit the calculation that ought to be made from the fact that the sixteen daily millions go mostly into English or British pockets, thence to British traders and, finally, to British banks in the form of cash or investment. Rates have never before been paid so promptly. The best financial advice we can give is this: if there is some necessary activity to be taken or work to be done, budget for it now. Especially look to your book fund: even though books are scarce, they are expensive. And have no faith in “financial after‐war promises.”

This is the fourth comprehensive register of current research in marketing to appear in this Journal. It is hoped that it will prove useful as a source of information to all those with interests in the subject. The projects listed do not include research work undertaken by commercial organisations or studies conducted in educational institutions where the results are not intended to be generally available. Otherwise, every effort has been made to obtain basic information from research workers willing to discuss their efforts with other interested individuals.

This paper aims to examine the design of optimal incentives for a firm’s tax department in the presence of information asymmetry.

This paper provides a theoretical model to examine the design of optimal incentives. The focus is on a situation in which a risk-averse tax department has private information about its efficiency type or effort to be exerted before the firm sets the incentive schemes.

This paper shows that a tax department’s risk aversion leads to a decline in the fraction of the cost borne by the tax department. It also shows that the optimal contract schemes should be designed to filter out as much uncontrollable risk as possible by using third-party information relevant to a tax department’s realized cost.

It contributes to a better understanding of the impact of corporate incentive plans on firms’ tax practices. This study, by designing a theoretical model, helps explain why there exist differences in tax planning across firms based on the finding that incentives for tax planning activities differ across firms.

This paper is the first study that considers the situation in which tax managers’ risk-averse and types, as well as relevant information collected by the firms, can be used to set up incentive schemes and investigates whether and how the incentive schemes will be affected when firms improve their prior information by acquiring relevant information before the tax department acts.

The employer brand is a crucial intangible asset for companies as it enhances the employer–employee relationship, leading to improved employee performance and overall company outcomes. This paper aims to investigate the contribution of the employer brand to the financial results of companies in southern Europe.

The sample consists of 266 companies operating in southern European countries during the year 2020. Secondary data on employer brand attributes, assessed from the perspective of current employees, were collected from the Glassdoor platform. Financial indicators were obtained from the companies' annual financial reports. The research hypotheses were tested using regression analysis.

The results of the regression analysis support the notion that the employer brand contributes to profitability indicators and management effectiveness indicators of southern European companies. However, the study did not find evidence supporting the contribution of the employer brand to market indicators and financial structure indicators of the observed companies.

This study is one of the first empirical investigations to assess the role of the employer brand as a human capital tool for enhancing the financial performance of companies in southern Europe. The study examines employer brand attributes from the perspective of current employees, who actively participate in shaping the employer brand and the company's image. In contrast to prior research, this study incorporates a more extensive set of financial indicators, categorized into four groups: profitability indicators, management effectiveness indicators, market indicators and financial structure indicators.