Equipment Quantities Research Articles

An efficient mixed-variable generation operator for integrated energy system configuration optimization

Energy consumption has skyrocketed as society has progressed, resulting in energy crises and environmental issues. New energy technologies are being developed to address these challenges, and technologies such as the cogeneration of electricity, heating, and cooling are being used to improve energy utilization. The configuration of an energy system has a critical impact on the economics of the system, its ability to supply energy, etc. This study establishes a multiobjective mixed-variable configuration optimization model for a comprehensive combined cooling, heating, and power energy system. The model considers equipment types (categorical variables), equipment quantities (integer variables), and critical parameters (real variables) as optimization variables, where economic performance, the proportion of renewable energy, supply shortage, and dependence on the external power grid are considered unoptimized objectives. This is a multiobjective and mixed-variable problem, and the combination of the two properties poses an excellent challenge for evolutionary algorithms in optimizing the model. Therefore, we propose an efficient generating operator based on a fully connected weighted neural network, called the FCWN operator. This operator overcomes the challenge of the discrete variable space and broken neighborhood relationships in mixed-variable problems. During the algorithm search process, search history information is used to update the fully connected weight network for distribution estimation of the variable space. Offspring are generated based on the fully connected network to improve the algorithm’s search efficiency. In the experimental section, we construct a model with 20 variables and conduct simulation-based configuration optimization for scenarios with 3, 5, and 8 available equipment types. The final obtained Pareto frontier solution set is evaluated using the hypervolume metric, a widely used multiobjective evaluation metric. The Wilcoxon rank sum test on the experimental results shows that the proposed algorithm has better results than other state-of-the-art algorithms at a 95% confidence level.

Selecting a Cargo Aircraft for Humanitarian and Disaster Relief Operations by Multicriteria Decision Aid Methods

Airlift operations are vital to support contingency plans during the major humanitarian and disaster relief (HDR) events. The access to disaster zones is often limited by unsafe conditions, poor road infrastructure, and lack of commercial air services. To overcome these limitations, the development of larger planes has allowed bulkier equipment and larger quantities of supplies to be transported by fewer flights. Embraer developed the KC-390 airplane to carry out logistics support and HDR missions. Multinational HDR events usually call for a wide variety of aircraft. The comparison between the KC-390 and the C-130 gains relevance under these circumstances, where the two will be competing for use in emergency support. This article aims to provide support for the allocation of the appropriate aircraft to each mission, by quantifying the advantages (and possible disadvantages) of the KC-390 compared with the C-130 based on the relative difference of their technical performance. Consolidated scores are established through the probabilistic composition of preferences by combining preference probabilities using weighted sums. The weights are calculated based on the experience of pilots applying the analytical hierarchical process. Among the types of missions analyzed, search and rescue present the highest difference in technical performance, in favor of the KC-390.

Multi‐objective optimal configuration method for a standalone wind–solar–battery hybrid power system

With the development of the energy internet, the standalone wind–solar–battery hybrid power system has gradually become an effective means for the complete utilisation of clean energy for power generation. The allocation of the various types of power sources for ensuring a reliable power supply and for improving the economic efficiency of a system is a crucial issue in the system planning and design stages. The models of the power load and the power sources, containing random components, are first established in this study, based on which the power supply reliability and constraint conditions for the equipment quantities are considered for establishing various evaluation indexes for improving the system performance. Then, according to the combinations of the natural selection particle swarm optimisation algorithm and the weight coefficient transform method, a multi-objective optimisation algorithm is proposed for optimising the configuration of a standalone wind–solar–battery hybrid power system. Finally, it is demonstrated by an example that the optimisation method not only meets the requirements of the multi-objective optimisation system but is also significant in reducing energy wastes and fluctuations, cost saving, and in ensuring the reliability of the power supply.

Characterization of monitor recycling in Seattle, Washington

With the rapid growth of electronic waste (e-waste), policies that aim to effectively manage this waste stream have been introduced globally in recent years. Seattle, Washington, has been on the forefront of introducing policies to divert e-waste from the landfills and maximize recycling. With the introduction of the Take-it-Back-Network, a solid recycling infrastructure has existed in the Greater Seattle region since 2003. In 2009, the E-Cycle Washington program took into effect and now allows recyclers to offer free recycling of certain e-waste to households and small entities. Although policies to divert e-waste from the landfill to reuse and recycling is effective, there is also a need to analyze the current regional recycling infrastructure’s capacity to handle changing equipment and material quantities. This study aims to characterize the Seattle regional e-waste management capacity, with a focus on retired monitors as an example of a changing e-waste technology. We investigated waste computer monitor recycling in the Greater Seattle region, which includes the counties of King, Pierce, Snohomish, and Kitsap. Interviews were conducted on 20 collectors, 1 handler, and 2 processors to collect information on their business models, computer monitor management processes, and collection/processing quantities. Using this information, we summarize the material flows of end-of-life (EOL) cathode ray tube (CRT) and liquid crystal display (LCD) monitors in the region, both from the qualitative and quantitative perspective.

空コンテナの回送を考慮したコンテナ船のロケーション・ルーチング問題

For recent years, container traffic has been growing, especially in East and Southeast Asia. However, most liner shipping companies make an effort to select calling ports, in particular taking into account effective plans of an efficient repositioning of equipment in use based on a prediction of when and where imbalance in equipment quantities will occur. Therefore, the decision maker of a container liner company should maximize the company's profit with considering the above issue. In this paper, we propose a design method of containership routing networks as the shuttle type of the location routing problem on the set partitioning problem basis. The proposed method gives the solution as a set of calling ports, shipping routes, the number ships by ship's speed and size. An application of the problem to container transportation in Southeast Asia is presented. By numerical simulation studies, we evaluated routing alternatives of several ship sizes and examined the effect of consideration of equipment imbalance in composing the shipping routes.

Reflections on the traffic usage recorder with emphasis on traffic engineering

As implied by the title, the intent of this article is to relate the manner of use and value of the Traffic Usage Recorder as applied to telephone traffic engineering. To develop a full appreciation of this, a general knowledge of the responsibility of the traffic engineer is required. In a broad sense, the traffic engineer must see that facilities of the right kind and of the right amounts are in the right place at the right time to give the right grade of telephone service. An important phase in this provision of telephone facilities is in determining the requirements of the telephone subscriber. In the process of estimating subscriber requirements, summarized call carrying and associated equipment usage data are analyzed, projected, and modified to reflect expected growth, new service, and proposed equipment arrangements. The modified basic data are then converted to equipment quantities and trunks through the use of probability tables reflecting the desired grades of service. The first step of this process, the gathering and summarization of usage data, is of prime importance and has been a major problem to the traffic engineer.

Subdivision of telephone traffic

Traffic data for engineering of telephone switching equipment is usually derived from traffic measurements extended over as large a number of circuit groups and as long periods of observation as practical. The quantities of equipment required in circuit subgroups are then based on the average traffic, prorated to the particular subgroup. The factors governing this averaging process will be analyzed under case I. The converse process, where the total traffic is estimated from observation on a few sample subgroups, is less often used in engineering equipment quantities. In latter instance, Case II, standard methods of statistical estimation are applicable, with additional adjustments which correspond to those discussed herein.