Faten Rafeh, Hussein Mroueh, Karim Hitti and Sebastien Burlon
The presence of underground quarries in North France in close proximity to urbanized areas, imposes serious problems in terms of security of both people and constructions at one…
Abstract
Purpose
The presence of underground quarries in North France in close proximity to urbanized areas, imposes serious problems in terms of security of both people and constructions at one hand, and induces a strong constraint against planning and urban development on the other hand. The purpose of this paper is to provide a practical tool for the preliminary estimation of the stability of underground quarries.
Design/methodology/approach
In this paper, a numerical stability study of quarries, excavated in chalk of North France with or without joints, by the method of rooms and pillars, is presented. This integrates the data provided from site: mechanical properties of the chalk and geometric characteristics of the quarries (width of the pillar W, height of the pillar H and span between pillars L), as well as the orientation of the joints (α). Numerical parametric analysis is conducted using FLAC 3D. Factors of safety are computed from the numerical models. Then, a second-order regression technique is applied on these numerically obtained factors, to correlate new formulae.
Findings
As a result, user-friendly formulae for the calculation of factors of safety Fs (ex) are extrapolated. Besides, abacuses to determine the minimum permissible effective width of safe pillars are proposed.
Originality/value
By this, it becomes possible, knowing only few parameters about geometry and properties, to give a fast estimation of the stability state of any quarry in the region.
Details
Keywords
Rafikul Islam, Kazi Md. Tarique and Siti Salwani Razali
The Takāful (Islamic insurance) industry operates on the principles of Maqāṣid al-Sharī’ah, and of late, the industry has witnessed significant market growth. The purpose of this…
Abstract
Purpose
The Takāful (Islamic insurance) industry operates on the principles of Maqāṣid al-Sharī’ah, and of late, the industry has witnessed significant market growth. The purpose of this study is to develop a performance measurement model based on Maqāṣid al-Sharī’ah to evaluate the performance of Takāful firms.
Design/methodology/approach
A mixed-method research approach was adopted to conduct the present study. Priorities were assigned to various dimensions of the Maqāṣid model using analytic hierarchy process and by taking inputs from 18 Takāful experts. On the contrary, six experts were involved in identifying the elements and measures for the operationalization of the Maqāṣid dimensions.
Findings
Maṣlaḥa (0.359) was found to possess the highest priority, followed by Justice (0.345) and Educating Individuals (0.295). Furthermore, under Necessity, protection of religion (0.398) and protection of life (0.388) are assigned almost similar priorities. These two are followed by the protection of progeny (0.107), protection of wealth (0.058) and protection of intellect (0.047). The final outcome of this study is a hierarchical model for the evaluation of performance of Takāful firms.
Practical implications
The application of the performance evaluation model will provide information to the management of Takāful firms on where they stand in terms of fulfilling Maqāṣid al-Sharī’ah principles. If any firms are found to have a deficiency in a certain part of Maqāṣid components, then proper and adequate measures can be taken to ameliorate the situation.
Originality/value
It is necessary to have a performance evaluation model based upon Maqāṣid al-Sharī’ah to evaluate the performance of Takāful firms as these firms operate on the principles of Maqāṣid al-Sharī’ah. Because there does not exist any such model, this study fills up this gap. Details of the measures that can be used to evaluate the performance of Takāful firms are also provided.
Details
Keywords
Shaoyi Liu, Song Xue, Peiyuan Lian, Jianlun Huang, Zhihai Wang, Lihao Ping and Congsi Wang
The conventional design method relies on a priori knowledge, which limits the rapid and efficient development of electronic packaging structures. The purpose of this study is to…
Abstract
Purpose
The conventional design method relies on a priori knowledge, which limits the rapid and efficient development of electronic packaging structures. The purpose of this study is to propose a hybrid method of data-driven inverse design, which couples adaptive surrogate model technology with optimization algorithm to to enable an efficient and accurate inverse design of electronic packaging structures.
Design/methodology/approach
The multisurrogate accumulative local error-based ensemble forward prediction model is proposed to predict the performance properties of the packaging structure. As the forward prediction model is adaptive, it can identify respond to sensitive regions of design space and sample more design points in those regions, getting the trade-off between accuracy and computation resources. In addition, the forward prediction model uses the average ensemble method to mitigate the accuracy degradation caused by poor individual surrogate performance. The Particle Swarm Optimization algorithm is then coupled with the forward prediction model for the inverse design of the electronic packaging structure.
Findings
Benchmark testing demonstrated the superior approximate performance of the proposed ensemble model. Two engineering cases have shown that using the proposed method for inverse design has significant computational savings while ensuring design accuracy. In addition, the proposed method is capable of outputting multiple structure parameters according to the expected performance and can design the packaging structure based on its extreme performance.
Originality/value
Because of its data-driven nature, the inverse design method proposed also has potential applications in other scientific fields related to optimization and inverse design.