A Criterion Space Branch-and-Cut Algorithm for Mixed Integer Bilinear Maximum Multiplicative Programs

This study introduces a branch-and-bound algorithm to solve mixed-integer bilinear maximum multiplicative programs (MIBL-MMPs). This class of optimization problems arises in many applications, such as finding a Nash bargaining solution (Nash social welfare optimization), capacity allocation markets, reliability optimization, etc. The proposed algorithm applies multiobjective optimization principles to solve MIBL-MMPs exploiting a special characteristic in these problems. That is, taking each multiplicative term in the objective function as a dummy objective function, the projection of an optimal solution of MIBL-MMPs is a nondominated point in the space of dummy objectives. Moreover, several enhancements are applied and adjusted to tighten the bounds and improve the performance of the algorithm. The performance of the algorithm is investigated by 400 randomly generated sample instances of MIBL-MMPs. The obtained result is compared against the outputs of the mixed-integer second order cone programming (SOCP) solver in CPLEX and a state-of-the-art algorithm in the literature for this problem. Our analysis on this comparison shows that the proposed algorithm outperforms the fastest existing method, that is, the SOCP solver, by a factor of 6.54 on average. Summary of Contribution: The scope of this paper is defined over a class of mixed-integer programs, the so-called mixed-integer bilinear maximum multiplicative programs (MIBL-MMPs). The importance of MIBL-MMPs is highlighted by the fact that they are encountered in applications, such as Nash bargaining, capacity allocation markets, reliability optimization, etc. The mission of the paper is to introduce a novel and effective criterion space branch-and-cut algorithm to solve MIBL-MMPs by solving a finite number of single-objective mixed-integer linear programs. Starting with an initial set of primal and dual bounds, our proposed approach explores the efficient set of the multiobjective problem counterpart of the MIBL-MMP through a criterion space–based branch-and-cut paradigm and iteratively improves the bounds using a branch-and-bound scheme. The bounds are obtained using novel operations developed based on Chebyshev distance and piecewise McCormick envelopes. An extensive computational study demonstrates the efficacy of the proposed algorithm.

An efficient routing strategy for coupled spatial networks

The study of traffic dynamics on couple networks is important for the design and management of many real systems. In this paper, an efficient routing strategy on coupled spatial networks is proposed, considering both traffic characteristics and network topology information. With the routing strategy, the traffic capacity can be greatly improved in both scenarios of identical and heterogeneous node capacity allocation. Heterogeneous allocation strategy of node delivery capacity performs better than identical capacity allocation strategy. The study can help to improve the performance of real-world multi-modal traffic systems.

Thought on Establishing the Joint Prevention, Control and Disposal Mechanism of Medical Waste Under the COVID-19 Epidemic

A range of shortcomings was exposed in China’s medical waste disposal capabilities in responding to public health emergencies under outbreak of the novel coronavirus pneumonia (COVID-19) epidemic. Especially, the traditional medical waste disposal capacity allocation and the prevention and control mechanism oriented to “a single city” have been far from meeting the needs of medical waste disposal and management during the emergency period. Therefore, suggestions on establishing the regional joint prevention, control and disposal mechanism of medical waste were put forward in this paper with reference to the ideas of China’s existing regional joint prevention and control mechanism for air and water pollution, which covered the aspects of establishment of coordinating agencies, cross-regional collaborative disposal, cross-regional joint response to emergencies, cross-regional collaborative management and effectiveness evaluation.

Relationship between installed capacity with total installation cost on solar PV among prosumer NEM 2.0 in Malaysia

Generate energy by Solar PV installation among prosumer, i.e; domestic, commercial, industrial as well as agriculture for self-consumption under Net Energy Metering (NEM) system become more popular in Malaysia. One, if not the only reason, is that day-to-day installation costs are kept at a decreasing rate and this is one of the reasonable ones for future investments and energy savings. By considering this issue, this study is motivated to investigate the relationship between installed capacity with the total installation costs as represented by equipment costs, installed costs, and operating costs. Secondary data was utilized provided by Sustainable Energy Development Authority (SEDA) Malaysia and retrieved from Malaysian Energy Information Hub (MEIH). The data is then run by multivariate regression, which is focused on the random and fixed-effect model. Overall, the findings indicate that there is a significant relationship between installed capacities with total installation costs among all categories of the prosumer in Malaysia. It would be recommended that the policymaker can increase the quota capacity allocation to the prosumer since the costs are at a diminishing rate that led to the take-up rate increase.