| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Agrawal, Tarun, 1989, et al.
(författare)
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Automating Loading and Unloading for Autonomous Transport: Identifying Challenges and Requirements with a Systems Approach
- 2023
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Ingår i: IFIP Advances in Information and Communication Technology. - 1868-4238 .- 1868-422X. ; Part III, s. 332-345
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Konferensbidrag (refereegranskat)abstract
- The logistics industry has undergone significant changes due to high demand, competition, cost pressures, interruptions, and labor market limitations affecting supply chains. As a result, there has been a significant adoption of automation in internal logistics such as warehousing, stock control, and material handling, leading to increased organizational competitiveness by reducing manual labor costs and time spent on these operations. The use of autonomous road transport holds potential to improve transport performance within areas of safety, sustainability, and efficiency. However, for autonomous transport to be fully ealized, loading and unloading processes at shipping and receiving facilities must also be automated. This paper takes a systems approach to identify the challenges and requirements for automated loading and unloading in a setting of autonomous truck transport potentially within a production setting. By addressing these challenges and meeting the necessary requirements, it may be possible to fully realize the benefits of autonomous transport and improve overall transport performance.
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| 3. |
- Browne, Michael, et al.
(författare)
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MIND THE GAP: THE INTERFACE BETWEEN AUTONOMOUS VEHICLES AND THE LOGISTICS SYSTEM
- 2020
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose Using autonomous vehicles in goods transport has potential benefits. However, the transition to a future autonomous (and electric) freight system needs to take account of the interface between the vehicle and other parts of the logistics system in order to exploit potential benefits and overcome challenges related to the absence of a driver. The purpose of the research is to identify the prerequisites for achieving automated loading, unloading, related information handling and in-plant transport at these interfaces. Research Approach Cases studies consider senders and receivers of various products as well as organisations that have a role including real estate companies that develop warehouses and terminals. The case studies consider vehicle and handling equipment technology alongside the processes that may need to change if the efficiency gains of an autonomous vehicle are to be realised. Research questions are addressed at the logistics system level. The cases studies combine questions about logistics process and technology alongside those concerned with underlying business models. Findings and Originality Results presented are at the half way stage of a two-year project and will be based on the initial series of interviews for four case studies. Findings so far include: (1) lack of development in this topic compared with interest in autonomous and automated transport (2) importance of organisational ssues in the logistics chain e.g. contractual relationships (3) importance of taking a broad view of the companies that need to be involved (4) product type and characteristics are important but other factors may have more influence on the scope to develop initiatives in this area. Research Impact The research provides insights into the complexity of the interfaces in autonomous and automated transport and logistics systems. The empirical findings enrich the discussion of this field. Combining insights from logistics, technology, materials handling and business has demonstrated the benefits of an interdisciplinary approach. Practical Impact Autonomous transport systems may bring many commercial benefits. However, the scale of these benefits will be significantly diminished if questions about the interface points in the logistics system are not addressed. The outputs of the research will provide important insights for managers addressing these challenges.
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| 4. |
- Browne, Michael, et al.
(författare)
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Partnerships among Stakeholders
- 2014
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Ingår i: City Logistics: Mapping The Future. - : CRC Press. - 9781482208924 ; , s. 13-24
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Browne, Michael, et al.
(författare)
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Transportation as a loosely coupled system: a fundamental challenge for sustainable freight transportation
- 2022
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Ingår i: International Journal of Sustainable Transportation. - : Informa UK Limited. - 1556-8318 .- 1556-8334. ; 17:7, s. 804-814
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Tidskriftsartikel (refereegranskat)abstract
- In view of the pressing need to reduce the negative environmental impact of freight transportation we argue that it is essential to take account of the organization of the freight transportation system when considering how to address various individual activities and parts of the system. To support a transition to a more sustainable freight transportation system this paper examines the way in which different parts of the system interact and the way this can impact the scope for profound change. Taking loosely coupled systems (Weick, 1976) as a starting point, we scrutinize the couplings within and between three system layers of the freight transportation system: the supply chain layer, the transportation layer, and the infrastructure layer. In addition, we address two interfaces connecting these layers: the market for transportation services, and the traffic using the infrastructure. We find that tight couplings dominate in the supply chain and infrastructure layers and that these couplings depend on loose couplings in the transportation layer and the two interfaces. The pattern of couplings identified in the freight transportation system can explain several positive outcomes, such as flexibility and efficiency. But there are also major negative aspects of the loosely coupled nature of the system that create resistance to change and present a barrier in the drive for increased sustainability. The paper concludes that the identified couplings and system features have important implications for policies aiming to change the freight transportation system in ways that lead to significant reduction in the reliance on oil.
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| 6. |
- Browne, Michael, et al.
(författare)
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Urban traffic congestion and freight transport: A comparative assessment of three European cities.
- 2017
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Ingår i: 3rd Interdisciplinary International Conference on Production, Logistics and Traffic, Darmstadt.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A high proportion of freight and service transport in cities takes place during peak hours on the road network. At the same time, trends in supply chains and logistics management together with changes in the behaviour by business and private consumers are leading to increased fragmentation of last mile deliveries. The combined result of this is that more vehicles are trying to make more deliveries at the same time and the infrastructure available (roadspace and curbside space) cannot cope. The paper explores this trend by means of a review in three contrasting cities: Stockholm, Brussels and London. The research is a qualitative assessment of trends and developments focused on freight transport and congestion. The three cities suffer from problems of congestion and all have a growing number of smaller vehicles being used in urban supply chains. This has consequences for congestion patterns. All three cities also face greater increases in freight transport activity compared with personal car travel. The scope to retime deliveries to the off peak hours (OHD) is important and some progress has been made although it is limited. The comparisons provide some insights and give ideas for further changes.
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| 7. |
- Fried, Travis, et al.
(författare)
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Evaluating spatial inequity in last-mile delivery: a national analysis
- 2024
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Ingår i: International Journal of Physical Distribution and Logistics Management. - 0960-0035. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Despite large bodies of research related to the impacts of e-commerce on last-mile logistics and sustainability, there has been limited effort to evaluate urban freight using an equity lens. Therefore, this study proposes a modeling framework that enables researchers and planners to estimate the baseline equity performance of a major e-commerce platform and evaluate equity impacts of possible urban freight management strategies. The study also analyzes the sensitivity of various operational decisions to mitigate bias in the analysis. Design/methodology/approach: The model adapts empirical methodologies from activity-based modeling, transport equity evaluation, and residential freight trip generation (RFTG) to estimate person- and household-level delivery demand and cargo van traffic exposure in 41 U.S. Metropolitan Statistical Areas (MSAs). Findings: Evaluating 12 measurements across varying population segments and spatial units, the study finds robust evidence for racial and socio-economic inequities in last-mile delivery for low-income and, especially, populations of color (POC). By the most conservative measurement, POC are exposed to roughly 35% more cargo van traffic than white populations on average, despite ordering less than half as many packages. The study explores the model’s utility by evaluating a simple scenario that finds marginal equity gains for urban freight management strategies that prioritize line-haul efficiency improvements over those improving intra-neighborhood circulations. Originality/value: Presents a first effort in building a modeling framework for more equitable decision-making in last-mile delivery operations and broader city planning.
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| 8. |
- Fried, T., et al.
(författare)
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Seeking equity and justice in urban freight: where to look?
- 2024
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Ingår i: Transport Reviews. - 0144-1647 .- 1464-5327. ; 44:1, s. 191-212
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Tidskriftsartikel (refereegranskat)abstract
- Urban freight systems embed and reflect spatial inequities in cities and imbalanced power structures within transport decision-making. These concerns are principal domains of "transportation justice" (TJ) and "mobility justice" (MJ) scholarship that have emerged in the past decade. However, little research exists situating urban freight within these prevailing frameworks, which leaves urban freight research on socio-environmental equity and justice ill-defined, especially compared to passenger or personal mobility discussions. Through the lens that derives from TJ and MJ's critical dialogue, this study synthesises urban freight literature's engagement with equity and justice. Namely, the review evaluates: How do researchers identify equitable distributions of urban freight's costs and benefits? At what scale do researchers evaluate urban freight inequities? And who does research consider entitled to urban freight equity and how are they involved in urban freight governance? The findings help inform researchers who seek to reimagine urban freight management strategies within broader equity and justice discourse.
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| 9. |
- Hanson, Robin, 1981, et al.
(författare)
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Challenges and requirements in the introduction of automated loading and unloading
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Research question The use of autonomous vehicles for road transport holds a potential to improve transport performance within areas such as safety, sustainability, driver shortage, and cost efficiency, and there is an increasing interest in the area (Sindi and Woodman, 2021). However, to fully realise the potential of autonomous transport, it seems that the interfaces with shipping and receiving facilities, in terms of loading and unloading, should be automated too, as argued below.In traditional setups, the truck driver is often responsible for loading and unloading the truck, as well as for securing the load. Hence, if there is no truck driver, a different solution is required. A straightforward solution would be for the personnel in the facilities to perform the loading and unloading. Increasingly, however, automation is applied also in production (Bortolini et al. 2021) and warehousing (Custodio and Machado 2020), and it is therefore not obvious that there will be personnel available at the pickup or delivery locations either. Moreover, it is not uncommon that facilities are manned only during daytime. Automated loading and unloading operations could make it possible to decouple the truck transports from the operations in the facilities, thereby enabling round the clock deliveries, regardless of the manning of the facilities. This could reduce congestion on the road. The application of automation often holds a potential to reduce operational cost, as the cost of man-hours may be reduced, which has been indicated in research on internal transport (Bechtsis et al. 2017), as well as the broader area of materials handling. There are several potential challenges that need to be overcome, and several requirements that need to be fulfilled, to enable automated loading and unloading between the autonomous transport and the shipping and receiving facilities. The loading and unloading processes can be considered to take place in the interface between different systems, linking the shipping facilities with the external transport, and linking the external transport with the receiving facilities. In addition to moving the goods onto and off the truck, there are further activities that need to be undertaken, which are performed manually in most systems today. This includes for example opening and closing the hatch of the truck and, importantly, securing the load on the truck after loading it. Applying a systems approach, this paper addresses the question: which are the challenges and requirements of automated loading and unloading in a setting of autonomous freight road transport? Brief overview of the state of the art, including relevant references Significant research in past focused on simulating and automating loading and unloading operations on transportation system with truck driver (Shen et al. 2019; Cao and Dou 2021). They are primarily focused on planning of loading and unloading system and defining the working principles of systemsmodules compatible with multiple material, For instance, Xu et al. (2021). Stacking of standard pallets on truck with fully automated forklifts (Cao and Dou 2021), design and development of automatic cargo batch system for loading and unloading operations (Lee et al. 2014), design and development of automated guided vehicle for material handing in production (Thylén 2022) and application of digital twin technology in design and develop of an intelligent control system for automatic loading and unloading (Zhu, Xu, and Zhu 2021). Nevertheless, when it comes to unmanned fully autonomous transportation, studies on designing and realizing interfaces with shipping and receiving facilities, are limited and at nascent stage. Working towards addressing this research gap, this study identified challenges and requirements of automated loading and unloading in a setting of autonomous truck freight road transport. Method The paper is based on a case study at a production site where autonomous truck transport is currently applied in a pilot setup. In the pilot setup, goods are delivered by an autonomous truck from a production plant to a nearby warehouse, located a few hundred metres from the plant, although travelling partly on a public road. Connected to the pilot setup, preparations are also made for applying automated loading and unloading of the autonomous truck. The study is led by researchers from two universities and is conducted in cooperation with representatives from several companies. All the companies are participating in the preparations for automated loading and unloading at the production site: themanufacturing company operating the production plant and the warehouse, the company providing the autonomous truck, a company providing equipment for automated materials handling, and a company specializing in solutions for load securing. Data is collected through site visits and mapping of processes and material flows, as well as through interviews with the companies involved in the pilot setup and in the preparations for automated loading and unloading. Analysis and results The results from the first stage of the project have been used to prepare a base case with a conventional truck and driver used to move pallets between the production plant and the warehouse. A second case uses an autonomous truck to transport the pallets from the production plant to the warehouse. For the base case the truck is loaded by the driver using a forklift truck (FLT) and the driver secures the load. Unloading at the warehouse is done by FLT operated by someone working in receiving area. For the second case (autonomous truck) the vehicle is loaded by FLT operated by someone from the production plant. Unloading is the responsibility of the warehouse receiving the pallets and is therefore the same as the base case operation.Mapping the material flows and the steps involved has shown that the driver plays various roles beyond driving the truck between the plant and the warehouse. These roles include: opening the door/gate at the loading bay, loading the truck with pallets, securing the load, deciding when the truck is full and needs to leave the plant to go to the warehouse and informing the staff at the warehouse that the truck has arrived. After unloading the driver will determine whether the truck should go back to the production plant for another load or should be used for another activity at the production location. When the autonomous truck is used then the ancillary actions carried out by the driver (listed above) have to be done by someone else or a change has to be made to the processes – for example a sensor could indicate the arrival at the warehouse of the loaded truck. Mapping the processes has demonstrated the scale of the challenge in automating these activities and the requirements applying to an automated loading and unloading system. These include the dynamic environment of the loading/unloading area, non-uniformity of goods, scanning of goods (identification tag, ensuring even weight distribution and alignment of pallets, securing of the load). The accountability and responsibilities of different stakeholders in fully automated unmanned system and handling of claims must also be addressed in the change to more automated systems.
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