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During drilling in coal mines, sticking of drill rod (referred to as SDR in this work) is a potential threat to underground safety. However, no practical measures to deter SDR have been developed yet. The purpose of this study is to develop an anti-SDR strategy using proportional-integral-derivative (PID) and compliance control (PIDC). The proposed strategy is compatible with the drilling process currently used in underground coal mines using drill rigs. Therefore, this study aims to contribute to the PIDC strategy for solving SDR.

A hydraulic circuit to reduce SDR was built based on a load-independent flow distribution system, a PID controller was designed to control the inlet hydraulic pressure of the rotation motor and a typical compliance control approach was adopted to control the feed force and displacement. Moreover, the weight and optimal combination of the alternative admittance control parameters for the feed cylinder were obtained by adopting the orthogonal experiment approach. Furthermore, a fuzzy admittance control approach was proposed to control the feed displacement. Experiments were conducted to test the effectiveness of the proposed method.

The experimental results indicated that the PIDC strategy was appropriate and effective for controlling the rotation motor and feed cylinder; thus, the proposed method significantly reduces the SDR during drilling operations in underground coal mines.

As the PIDC strategy solves the SDR problem in underground coal mines, it greatly improves the safety of coal mine operation and decreases the power cost. Consequently, it brings the considerable benefits of coal mine production and vast application prospects in other corresponding fields. Actual drilling conditions are difficult to accurately simulate in a laboratory; thus, for future work, drilling experiments can be conducted in actual underground coal mines.

The PIDC-based anti-SDR strategy proposed in this study satisfactorily controls the rotation motor and feed cylinder and facilitates the feed and rotation movements. Furthermore, the tangible novelty of this study results is that it improves the frequency response of the entire drilling system. The drilling process with PIDC decreased the occurrence of SDR by 50%; therefore, the anti-SDR strategy can significantly improve the safety and efficiency of underground coal mining.

Digitalization and multi-channel strategy have appeared as recurrent themes in retailing for years, yet some major international as well as domestic mass retailers have chosen to retain a single, physical channel focus for customer transactions. These retailers, despite the digital mindset preoccupying the retailing sector, have chosen to rely fully, or predominantly, on their stores to generate revenues. A number of questions arise from this approach. This paper aims to understand the rationale for marketing and strategic practices which appear to go against the dominant, strongly digitally oriented, discourses and practices in the field of retailing. Why do some retailers choose not to add a digital transactional channel? Are there defensible reasons for this choice? Can such a strategy successfully create value?

This research is based on a qualitative, multiple case study of the strategies adopted by Primark (fashion) and Aldi (food), two major retailers that retain a largely single-channel transaction focus, in France and the UK.

This research suggests that some retailers may still be able to succeed by maintaining a single-transactional physical channel to avoid a cost trap which extensive moves towards digitalization of transactions might mean for them. In such circumstances, refusing to adopt a digital value proposition may be a means of preserving the success of their original business model.

Despite the weight of academic and practitioner discourses on the urge to undertake digital transformation, this work provides a comprehensive illustration of the rationale for sticking to a single physical channel to preserve the profitability of a traditional store-based business model.

The article investigates the institutional setup of e-lending in public libraries in Denmark, Norway and Sweden. Our point of departure is that e-lending has necessitated new library collaborations between local, regional and national levels, and therefore, institutional e-lending setups have emerged. The study seeks to provide better understanding of how the institutional setups are structured, how governance logics have shaped them and what tensions and dynamics become visible in the key actors’ problematisations of these setups.

The study is situated in the neo-institutional tradition and applies the institutional logics perspective. The research questions are answered by taking a qualitative approach, grounded in an extensive interview study with representatives of libraries, publishers and policy actors in three Scandinavian countries. To provide in-depth insight into e-lending setups, the scope of empirical material is then limited to accounts the central library and policy actors involved in establishing e-lending.

The analysis shows that the e-lending setups are both similar (especially when it comes to financing), and different across Scandinavia, especially when it comes to centralisation and involvement of librarians in this task. The differences are attributed to the influence of different governance logics (question of administrative autonomy, collaboration in the field and existing legal and political frames), and to what extent the digital and market logics are incorporated or rejected in the field.

The study provides new insights into the question of how Scandinavian public libraries face the consequences of the digitalisation of book distribution and consumption by investigating how they organise their e-lending services. This has not been explored before, notably in a comparative perspective.

This paper aims to propose a robust kinematic controller based on sliding mode theory designed to solve the trajectory tracking problem and also the formation control using the leader–follower strategy for nonholonomic differential-drive wheeled mobile robots with a PD dynamic controller.

To deal with classical sliding mode control shortcomings, such as the chattering and the requirement of a priori knowledge of the limits of the effects of disturbances, an immune regulation mechanism-inspired approach is proposed to adjust the control effort magnitude adaptively. A simple fuzzy boundary layer method and an adaptation law for the immune portion gain online adjustment are also considered. An obstacle avoidance reactive strategy is proposed for the leader robot, given the importance of the leader in the formation control structure.

To verify the adaptability of the controller, obstacles are distributed along the reference trajectory, and the simulation and experimental results show the effectiveness of the proposed controller, which was capable of generating control signals avoiding chattering, compensating for disturbances and avoiding the obstacles.

The proposed design stands out for the ability to adapt in a case involving obstacle avoidance, trajectory tracking and leader–follower formation control by nonholonomic robots under the incidence of uncertainties and disturbances and also considering that the immune-based control provided chattering mitigation by adjusting the magnitude of the control effort, with adaptability improved by a simple integral-type adaptive law derived by Lyapunov stability analysis.

The main objectives of the current study are to assess the existing situation of historical city centers in Iran and to offer prioritized appropriate regeneration strategies for their sustainable development.

The study is based on a questionnaire-based survey in four historical city centers of Iran: Kashan, Naeen, Ardakan and Yazd. The required data have been collected using multiple tools including questionnaires and interviews with local residents and officials in the aforementioned case studies. Using the strengths, weaknesses, opportunities and threats (SWOT) technique, a set of appropriate strategies for the sustainable regeneration of these valuable fabrics has been proposed and the best of them have been prioritized employing quantitative strategic planning matrix (QSPM) matrix.

The results show that the current situation in all the case studies is not in line with sustainability and cultural heritage protection. Their multiple problems are mostly associated with their weaknesses, whilst their strengths, including a considerable potential as a tourism attraction, are scarcely exploited. The experts and residents surveyed for this research have provided basic information to establish the conservative strategies that should take priority when preparing the urban regeneration process of these areas.

Since most of the adopted regeneration strategies in Iran are not supported by empirical studies, the current study largely fulfills this shortcoming by setting up a proper diagnosis of historical city centers in Iran and proposes the most appropriate regeneration strategies based on the findings.

This paper investigates the impact of family influence measured by the F-PEC scale on private enterprise (both family firms and lone founders) leadership succession strategy.

The research dataset is comprised of 390 private enterprises whose head offices were situated in the voivodeships of Lower Silesia and Wielkopolska in Poland. The authors collected data through CAPI (computer-assisted personal interviewing) method, as well as through comprehensive, structured interviews with company owners. Data were analysed using hierarchical logistic regression for each type of succession strategy.

The results suggest that increased family influence does not necessarily lead to intra-family leadership succession in private enterprises. Importantly, a range of findings contradicted authors' predictions. The relationship between the overall F-PEC scale values signifying the multi-faceted family influence over the business and the choice of internal successor was weakly negative for the total sample; also, the higher the overlap between family and business values and the higher the commitment to family business, as evidenced by the Culture subscale, the lower was the occurrence of intra-family successor choice in the population of lone founders. The Culture subscale also increased the prevalence of lack of succession planning in the sample of lone founders.

While several studies suggests that family firms may be more prone to choose an intra-family succession scenario, it remains unclear how lower levels of business and succession experience, may influence the successor choice. Indeed, some studies suggest that a strong family influence over a business, may stimulate family firms to choose a family outsider as a business leader. Therefore, the key contribution of this study is contextualizing the response to an ongoing succession debate. This study investigates the strategic choices of companies in the first generation of ownership operating in Poland, which serves as an example of a post-transition economy. While the characteristics of this economic environment may be unique, the authors discuss how the surprising findings may add to the understanding of the general succession processes present in private enterprises.

In metropolitan areas experiencing rapid urbanization and housing production, the size of housing units emerges as a crucial factor to consider in housing policy formulation. This study aims to focus on Turkey, a developing country undergoing rapid urbanization and a construction boom in recent years, to examine households’ housing size preferences. Through a detailed analysis, this research delves into the causal relationships between income, education and housing size preferences.

This study uses the Family Structure Survey in Turkey 2016 data set collected nationwide by the Turkish Statistical Institute (TurkStat). To address potential endogeneity issues related to income and education levels in households’ choice of house size, an extended regression model is used. In addition, survey weights are applied to the statistical model to generalize the results of the study.

The study demonstrates that household income correlates with an increase in house size, while household education is associated with a decrease in house size. Variables such as household age, composition and vehicle ownership are found to impact the choice of house size. Particularly, one-person and couple-only households tend to prefer smaller dwellings compared to others. Lastly, the results reveal that the influence of household composition on dwelling size varies according to household age.

This study presents a comprehensive analysis of the determinants influencing households’ housing size preferences within the framework of a developing country context, focusing on Turkey. It specifically offers insights into the causal impact of education and income levels on housing size preferences, as well as the intricate interplay between household characteristics in shaping these preferences.