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Reducing the computational workload by simplifying the analysis of karst foundations into a plane strain problem can yield significant advantages. Yet, such an approach fails in reproducing the engineering situation in a rigorous manner. In this regard, this paper proposes an upper-bound method that can effectively analyze the bearing capacity of three-dimensional karst foundations. This method is utilized to investigate the impact of various pile diameters, the ratio of roof thickness to pile diameter, and the ratio of cave width to pile diameter on the stability of karst foundations. The validity of this method is established through an illustrative example. The outcomes illustrate that when subjected to both tensile and compressive horizontal stresses if the maximum horizontal stress surpasses the tensile strength of the rock mass, the roof rock mass may suffer damage. Increasing the ratio of roof thickness to pile diameter can bring down the horizontal stress value. The stability factor is largely influenced by the ratio of roof thickness to pile diameter. The most prominent growth trend of the stability factor is observed when the ratio is less than 3. If the ratio of the roof thickness to pile diameter exceeds 3, the prediction of the bearing capacity estimation for the karst foundation in three-dimensional circumstances is more conservative than that in two-dimensional circumstances. [ABSTRACT FROM AUTHOR]

The Critical Path Method (CPM) has failed practically for scheduling repetitive projects and Line Of Balance (LOB) has emerged as an alternative for scheduling such projects. Because of the size of most repetitive projects, efficient resource management plays a vital role in their successful implementation. However, resource levelling and allocation have not been formally investigated in repetitive projects. Heuristic methods and optimization techniques have been traditionally used to solve resource scheduling problems like the latter. Although heuristic methods can handle large-size projects, they do not guarantee optimal solutions. In this paper, resource levelling and allocation problems under LOB scheme are modelled as an optimization problem that guarantees optimal solutions. Resource continuity and logical dependency between activities are maintained where constant activity progress rate is assumed. An example project is used to demonstrate the details of model formulation. A complete solution for the range of feasible project durations is obtained as a Time-Resource Trade-Off curve. A pipeline project is used to validate the developed model revealing that the developed model is superior. The proposed model provides contractors with a complete picture for resource usage along with the range of feasible project durations from which the optimal alternative can be selected. [ABSTRACT FROM AUTHOR]

As far as uncertainty is prevalent, financial anomalies increase the complexity of financial decisions. The possible consequence of an anomaly is either an over or underreaction. This paper suggests that the use of mathematical programming can lessen the degree of complexity when planning for financing, investment and dividend decisions. The authors develop a comprehensive form of the External Financing Needed model in order to show the generic and combined relationship among the three financial decisions. The comprehensive model shows nonlinear relationships between the three financial decisions. The paper uses a simulated numerical example to illustrate how financial objective functions (e.g. targets) can be set out under certain constraints. The latter serve as a remedy for financial anomalies. The results show that financing, investment and dividend decisions can be made optimally to serve having consistent financial statements. [ABSTRACT FROM AUTHOR]

For a nonlinear programming problem with equality constraints in a Hilbert space, a dual-type algorithm is constructed that is stable with respect to input data errors. The algorithm is based on a modified dual of the original problem that is solved directly by applying Tikhonov regularization. The algorithm is designed to determine a norm-bounded minimizing sequence of feasible elements. An iterative regularization of the dual algorithm is considered. A stopping rule for the iteration process is given in the case of a finite fixed error in the input data. [ABSTRACT FROM AUTHOR]

This work presents optimization results obtained for a double-effect H2O-LiBr absorption refrigeration system considering the total cost as minimization criterion, for a wide range of cooling capacity values. As a model result, the sizes of the process units and the corresponding operating conditions are obtained simultaneously. In this paper, the effectiveness factor of each proposed heat exchanger is considered as a model optimization variable which allows (if beneficial, according to the objective function to be minimized) its deletion from the optimal solution, therefore, helping us to determine the optimal configuration. Several optimization cases considering different target levels of cooling capacity are solved. Among the major results, it was observed that the total cost is considerably reduced when the solution heat exchanger operating at low temperature is deleted compared to the configuration that includes it. Also, it was found that the effect of removing this heat exchanger is comparatively more significant with increasing cooling capacity levels. A reduction of 9.8% in the total cost was obtained for a cooling capacity of 16 kW (11,537.2 $·year−1 vs. 12,794.5 $·year−1), while a reduction of 12% was obtained for a cooling capacity of 100 kW (31,338.1 $·year−1 vs. 35,613.9 $·year−1). The optimization mathematical model presented in this work assists in selecting the optimal process configuration, as well as determining the optimal process unit sizes and operating conditions of refrigeration systems. [ABSTRACT FROM AUTHOR]