Search Results (25)

The four-way shuttle storage and retrieval system (FWSS/RS) is an advanced automated warehousing solution for achieving green and intelligent logistics, and task allocation is crucial to its logistics efficiency. However, current research on task allocation in three-dimensional storage environments is mostly conducted in the single-operation mode that handles inbound or outbound tasks individually, with limited attention paid to the more prevalent composite operation mode where inbound and outbound tasks coexist. To bridge this gap, this study investigates the task allocation problem in an FWSS/RS under the composite operation mode, and deep reinforcement learning (DRL) is introduced to solve it. Initially, the FWSS/RS operational workflows and equipment motion characteristics are analyzed, and a task allocation model with the total task completion time as the optimization objective is established. Furthermore, the task allocation problem is transformed into a partially observable Markov decision process corresponding to reinforcement learning. Each shuttle is regarded as an independent agent that receives localized observations, including shuttle position information and task completion status, as inputs, and a deep neural network is employed to fit value functions to output action selections. Correspondingly, all agents are trained within an independent deep Q-network (IDQN) framework that facilitates collaborative learning through experience sharing while maintaining decentralized decision-making based on individual observations. Moreover, to validate the efficiency and effectiveness of the proposed model and method, experiments were conducted across various problem scales and transport resource configurations. The experimental results demonstrate that the DRL-based approach outperforms conventional task allocation methods, including the auction algorithm and the genetic algorithm. Specifically, the proposed IDQN-based method reduces the task completion time by up to 12.88% compared to the auction algorithm, and up to 8.64% compared to the genetic algorithm across multiple scenarios. Moreover, task-related factors are found to have a more significant impact on the optimization objectives of task allocation than transport resource-related factors. Full article

The concepts of sustainable development, triple bottom line, and ESG have a strong influence on the process of formation and operation of supply chains today. This requires the implementation of various green solutions and practices to improve supply chain sustainability. An analysis of supply chain research did not reveal a universally accepted methodology to systematize green solutions and practices for their effective use in chain management. It was revealed that there are many views on the content of green solutions, in addition to insufficient specificity of their description, as well as fragmentation of the use of green solutions in relation to the elements and functions of supply chains (procurement, production, warehousing, transportation, and distribution). This reduces the effectiveness of the implementation of green solutions. In this study, based on the literature review, a systematization of currently existing green solutions and practices was carried out. The systematization was performed according to the affiliation of supply chain elements and the functions performed by the elements to promote and process the material flow from supplier to consumer. The proposed system of methods (GLMs) and instruments (GLIs) of green logistics covers all known functional areas of logistics and includes 27 methods and 105 instruments. We performed a ranking of methods and instruments using TOPSIS, MABAC, and MARCOS methods. The most and least significant GLM and GLI for each element of the supply chain, as well as for chains of complex structure in general, were determined. The results of GLM and GLI ranking can be used as a basis for the implementation of management decisions to improve the sustainability of supply chains. Full article

With the rapid development of e-commerce, warehousing and logistics systems are facing the dual challenges of increasing order processing demand and green and low-carbon transformation. Traditional manual and single-robot scheduling methods are not only limited in efficiency, but will also make it difficult to meet the strategic needs of sustainable development due to their high energy consumption and resource redundancy. Therefore, in order to respond to the sustainable development goals of green logistics and resource optimization, this paper replaces the traditional mobile handling robot in warehousing and logistics with a composite robot composed of a mobile chassis and a robotic arm, which reduces energy consumption and labor costs by reducing manual intervention and improving the level of automation. Based on the traditional contract net protocol framework, a distributed task allocation strategy optimization method based on an improved genetic algorithm is proposed. This framework achieves real-time optimization of the robot task list and enhances the rationality of the task allocation strategy. By combining the improved genetic algorithm with the contract net protocol, multi-robot multi-task allocation is realized. The experimental results show that the improvement strategy can effectively support the transformation of the warehousing and logistics system to a low-carbon and intelligent sustainable development mode while improving the rationality of task allocation. Full article

Additive manufacturing and digital warehouses are transforming the way industries manage and maintain their spare parts inventory. Considering digital warehouses and on-demand manufacturing for spare parts during the project phase is a strategic decision that involves trade-offs depending on the operational needs and pricing structure. This paper aims to explore the spare part evaluation process considering both physical and digital warehouse inventories. A case asset is purposefully selected and four spare part management concepts are studied using a simulation modeling approach. The results highlight that the relevant digital warehouse scenario, used in this case, managed to completely reduce all emissions related to global spare parts supply; however, this was at the expense of reducing availability by 15.1%. However, the hybrid warehouse scenario managed to increase availability by 11.5% while completely reducing all emissions related to global spare parts supply. Depending on the demand rate, the digital warehousing may not be sufficient alone to keep the production availability at the highest levels; however, it is effective in reducing the stock amount, simplifying the inventory management, and making the supply process more green and resilient. A generic estimation model for spare parts engineers is provided to determine the optimal specifications of their spare parts supply and inventory while considering digital warehouses and on-demand manufacturing. Full article

Accelerating the construction and optimization of national value chains is of great significance to reducing both pollution and carbon emissions and promoting green economic growth. In accordance with the input–output table and carbon emission statistics of China in 2012, 2015, and 2017, in this paper, we use the total trade decomposition method and the value chain decomposition method to decompose the embodied carbon emissions and the embeddedness of national value chains. Subsequently, we empirically study, for the first time, the impact of the degree of domestic value chain embedding on implicit carbon emissions using the calculated results. The results show the following: (1) The top three provinces with embodied carbon emissions are Shandong, Hebei, and Jiangsu, while the top four industries are the production and supply of electricity and heat; metal smelting and rolling processing; non-metallic mineral products; and transportation, warehousing, and postal services. (2) The degree of forward and backward national value chain embeddedness in Chinese provinces has increased, and the degree of forward embeddedness in most provinces and industries is lower than that of backward embeddedness. (3) The embeddedness of domestic value chains and embodied carbon emissions is always negatively correlated, and this conclusion is still valid after robustness and endogeneity tests. (4) There is industrial heterogeneity in the impact of the degree of embeddedness of domestic value chains on embodied carbon emissions. Full article

Solar energy plays a crucial role in mitigating climate change and transitioning toward green energy. In China (particularly Northwest China), photovoltaic (PV) development is recognized as a co-benefit and nature-based solution for concurrently combating land degradation and producing clean energy. However, the existing literature on the subject is limited to the local effects of PV power station construction and ignores the spillover environmental effects in distant regions. Thus, a hotspot of PV development in Northwest China was selected as a case to quantify the spill-over impacts of PV development in Qinghai Province on cross-regional economy and the environment using an environmentally extended multi-regional input–output approach and related socioeconomic and environmental statistical data. A cross-regional carbon footprint analysis revealed that the eastern region of Qinghai Province had the highest carbon footprint, followed by the southwestern, central, southern, northwestern, northern, and northeastern regions; the production and supply sectors of electricity and heat were the primary sources of carbon emissions, followed by metal smelting and rolling processing products, non-metallic mineral products, and the transportation, warehousing, and postal sectors. In addition, the PV development in Qinghai Province strongly supports the electricity demand in the central and eastern coastal areas, while substantially reducing the carbon emissions in the eastern, southwestern, and central regions (through the distant supply of PV products). We quantified the spillover effects of PV development in Qinghai Province and address the challenges of PV development in the carbon emission reduction strategies implemented at the regional and cross-regional scales; our findings will support policymakers in developing plans that ensure sustainable energy supply and help China to achieve its carbon neutrality goals. Full article

As firms and consumers engage with environmental issues, decisions for inventory control need to entail this perspective of sustainability. Most green inventory models employ methods such as carbon caps or taxes for dealing with environmental sustainability. This problem can be more generally tackled via an explicit estimation of the environmental drivers of maintaining inventory in a warehouse, paired with the economic perspective within a transparent multi-objective optimization framework. With this goal, this paper builds on a detailed estimation of environmental and cost factors for a continuous-review inventory policy. The bi-objective problem is tackled by keeping the objective functions separate. In particular, the modeling of greenhouse gas emission or cost performance factors for the inventory encompasses factors that can depend on the decision variables, taking into account aspects such as warehouse location, building characterization, energy usage, and transport requirements. The effects of the emission drivers on the multi-objective optimization decisions are analyzed, considering that the problem can be constrained by multiple service level measures. Stockout response can be multifaceted and different service level measures capture different aspects of inventory shortages, affecting the resulting efficient solutions differently. The results highlight the impact of aspects such as warehouse location and supply capacity on solutions for the multi-objective inventory problem. Managerial decisions are thus influenced by warehousing and supply attributes via a traceable link to specific cost and emission determinants. Full article

With the tremendous development of the logistics industry, the global market of automated warehousing has been growing rapidly. Meanwhile, the warehousing industry shows drawbacks, such as low storage capacity and poor efficiency. By comparing and analyzing the shuttle-based storage and retrieval system (SBS/RS), miniload automated storage and retrieval system (AS/RS), and KIVA system, a novel efficient parts-to-picker approach in flexible warehousing systems is proposed. Among them, buffer racks and access racks, associated with the access of automated mobile robots (AMRs) and stackers are used. The results show that compared with other parts-to-picker systems (such as the KIVA system), this system provides a significant increase in storage capacity (more than three times), and the picking efficiency is also very high at various layout scales, where the picking efficiency is no less than the KIVA system when the number of AMRs reaches the max. The novel system is suitable for small-, medium-, and large-scale warehouses in terms of showing high capacity and producing excellent space utilization. More importantly, this system can easily compete with its traditional counterparts by using a layout of high density without much increase in cost. This sustainable improvement realizes the efficient utilization of spatial resources and provides important support for the construction of green supply chains. Full article

Stone fruits, such as the apricot (Prunus armeniaca L.), are frequently consumed. As such, a substantial volume of apricot waste is generated at each stage of the food supply chain, including harvesting, processing, packaging, warehousing, transportation, retailing, and eventual consumption. This generates tons of waste annually on a global scale. The significant amounts of phenolics present in these wastes are primarily responsible for their antioxidant capacity and the subsequent health advantages they provide. As such, apricot pulp by-products could be a valuable reservoir of bioactive compounds, such as tocopherols, polyphenolic compounds, proteins, dietary fibers, etc. Moreover, apricot kernels are also recognized for their abundance of bioactive compounds, including polyphenols and tocopherols, which find utility in diverse sectors including cosmetology and the food industry. Both conventional and green methods are employed, and generally, green methods lead to higher extraction efficiency. The antimicrobial properties of apricot kernel essential oil have been widely recognized, leading to its extensive historical usage in the treatment of diverse ailments. In addition, apricot kernel oil possesses the capacity to serve as a viable resource for renewable fuels and chemicals. This review examines the potential of apricot waste as a source of bioactive compounds, as well as its utilization in diverse applications, with an emphasis on its contribution to health improvement. Full article

The present consumer behavior is manipulated by “fast fashion”, where purchasing new, trendy, affordable clothes is preferred over recycling old ones. This changing mannerism has escalated the GHG emissions from the fashion industry. Energy-intensive raw material production, preparation, and processing contribute to considerable emissions. The management of the returned goods from the primary market and further processing through the secondary outlets indulge in reverse logistics. In this paper, efforts are made to minimize the total cost and the carbon emission amount during the process of managing the return articles from the primary market to the reverse distribution center, further processing of the articles at the secondary outlet, and the return of the unsold or excess articles from the secondary outlet. Reverse cross-docking has been implemented in managing the return articles, while environmental concerns over GHG emissions have been addressed by investing in green technology under a strict carbon cap policy. In this research, return articles from the primary and secondary markets, rework of the returned articles, and disposal of the impaired returned articles have been considered. The carbon emission cost at all stages of transportation, rework, or disposal has also been incorporated into this model. A constrained mixed integer linear programming model is proposed and solved considering green investment. A numerical example has been formulated to investigate the effect of green technology on the total cost. The results portray that, though the total cost increases by nearly 2% due to investment in green technology, it ensures a considerable drop of 23% in the carbon emission amount. Also, the result is successful in establishing that reverse cross-docking is a better option than traditional warehousing in terms of minimizing the cost. Full article

China’s economic development strategy is undergoing an evolution from foreign to domestic circulation mainly, and at the same time faces the rigid constraints of “carbon peak before 2030” and “carbon neutrality before 2060”. However, both domestic and foreign trade also have an important impact on carbon dioxide emissions. To this end, this paper uses China’s 2017 multi-regional Input-Output table to systematically simulate the impact of the new development pattern on carbon emissions from the comprehensive perspective of production and consumption. Our simulations find that when the foreign circulation disappears, the total economic output will be hit hard, and carbon emissions will be greatly reduced; when the foreign circulation orientation weakens and the intensity of the domestic circulation is increased, the total economic output will increase to varying degrees, but the total carbon emissions will also increase by a certain extent. Among them, the increase in carbon emissions at the living end accounts for a considerable proportion, while the carbon emissions of electricity, heat production and supply, transportation, warehousing and postal services, metal smelting and rolling processing industries at the production end increase more. From a policy perspective, the government should promote green production and green consumption to achieve a balance between economic growth and carbon emission reduction. Full article

The earth’s average temperature has risen by approximately 1.2 °C since the 1900s. The COP26 resolution aimed to achieve carbon neutrality before 2050, while China has committed a more aggressive timetable to actually achieve the goal. It requires either that activities must not release any greenhouse gases or the emitted greenhouse gases must be offset. The logistics and transport activities contribute a lot to global greenhouse gas emissions on Earth. There are a no. of challenges of the logistics industry that are discussed, then the paradigmatic solutions such as green procurement, green packaging, green transport, and green warehousing, are respectively discussed. The three contemporary concepts of green solutions (circular economy, carbon neutrality and green cocreation) for logistics and transportation are explored. Subsequently, a detailed case study of CN Logistics’ contemporary green solutions is used to illustrate how to tackle the problems and exemplify the best practices to the other 3PL players. There are expected changes on green directives from the HKSAR Government on logistics green compliances. Finally, this paper concludes with an appeal to the industry to start the green journey immediately. Full article

With the introduction of Society 5.0 for the sustainable future, special caution is given to humans’ role within the general system. Similarly, Industry 5.0 as a concept has been presented, followed by Logistics 5.0 in its theoretical framework. The transition towards the new concept of Logistics 5.0 requires an accurate and optimal strategic plan definition for which, in this paper, an implementation model based on decision support systems will be developed. The output data from this model are the priority of Logistics 5.0 elements (from five groups—green warehousing, green transport, green packaging, infrastructure and organization, and human resources) for the optimal implementation, based on three goals (initial investment, return of investment time, implementation and exploitation complexity) that companies aim to achieve in the future. The model is based on the analytic hierarchy process, and data were collected from an expert group and analyzed with several statistical methods. The result is a model that provides an optimal strategy for the implementation of elements of Logistics 5.0. The implementation priority list of elements is very beneficial for the management of many companies from various types of industries. Full article

Automatic warehousing systems are a sort of green technology that is becoming increasingly popular in the logistics business. Automated Storage/Retrieval Systems (AS/RS) are one of the most significant components of advanced automated logistics and manufacturing systems. The majority of AS/RS systems use input/output (I/O) points located in the lower left corner of the rack. These systems are reaching their maximum capacity because of their layout design limitations. Breakthrough solutions are needed to enhance the performance of existing systems. In this study, we examined how the location of I/O station can affect the total travel time. Another strategy for enhancement is a two-step preparation method. In this strategy, the allocation of the storage is changed, in the idle time, to be closer to the I/O point to reduce the service time for a class-based storage assignment. An analytical model was used to introduce for the first time optimal configurations of this strategy. We tested the suggested strategy using a simulation model created using R software, specifically designed for this purpose. Results showed that the two-step preparation strategy took between 1.2 and 1.9 h before the shift starts. The enhancement on throughput is almost the same for both possible locations of the I/O point. The results also showed that the two strategies (location of the I/O point and reallocation of storage) could increase throughput by about 21% to 28%, depending on parameters such as the number of orders and the height of the storage rack. Full article

Anthropogenic interferences through various intensive social-economic activities within construction land have induced and strengthened the Urban Heat Island (UHI) effects in global cities. Focused on the relative heat effect produced by different social-economic functions, this study established a general framework for functional construction land zones (FCLZs) mapping and investigated their heterogeneous contribution to the urban thermal environment, and then the thermal responses in FCLZs with 12 environmental indicators were analyzed. Taking Shenzhen as an example city, the results show that the total contribution and thermal effects within FCLZs are significantly different. Specifically, the FCLZs contribution to UHI regions highly exceeds the corresponding proportions of their area. The median warming capacity order of FCLZs is: Manufacture function (3.99 °C) > Warehousing and logistics function (3.69 °C) > Street and transportation function (3.61 °C) > Business services function (3.06 °C) > Administration and public services function (2.54 °C) > Green spaces and squares function (2.40 °C) > Residential function (2.21 °C). Both difference and consistency coexist in the responses of differential surface temperature (DST) to environmental indicators in FCLZs. The thermal responses of DST to biophysical and building indicators in groups of FCLZs are approximately consistent linear relationships with different intercepts, while the saturation effects shown in location and social-economic indicators indicate that distance and social-economic development control UHI effects in a non-linear way. This study could extend the understanding of urban thermal warming mechanisms and help to scientifically adjust environmental indicators in urban planning. Full article