Maxflow-Based Integrated Network Design and Scheduling Problems with Downgraded Capacities

This work examines CANDy and NDML concepts. CANDy, Computer Aided Network Design utility is a concept for an efficient XML-based integrated network design environment. Its integrating components are NDML (Network Design Markup Language), an XML-based problem-oriented language developed for representation of information components related to network projecting within documents. Its design supports interoperability with the XML family of tools and protocols. It provides a set of components to meet the needs of network design

The formulations of the user-optimal dynamic traffic assignment (UODTA)-based network design problem (NDP), signal setting design problem (SSD), and the integrated NDP and SSD problem (NDP-SSD) for the deterministic (DET), stochastic (SP) and robust (RO) optimizations are reviewed. The modifications of the simulated annealing (SA), genetic algorithm (GA) and reactive tabu search (RTS) for the nine problems (DET/SP/RO of NDP/SSD/NDP-SSD) are discussed. In the experiment, SA, GA and RTS are compared for the nine problems to identify best algorithms. The best algorithm for each problem is employed to find a best solution, which is then evaluated under stochastic condition. We find that the RO solutions yield the best robustness and lowest risk, whereas the DET solutions perform worst. The integrated robust approach is the most desirable, and the next best approach is the sequential robust approach. The deterministic approach can yield worse solutions than the do-nothing case.

To identify the sustainability synergies in a collaborative Moroccan dry food wholesale chain, we investigate the financial and ecological effects of implementing horizontal cooperation between three competitor shippers. For business-to-business networks, the key objective is to ensure last-mile delivery to their clients in metropolitan areas. The implementation of this alliance requires studying different aspects, among them the design of the transportation network, fair profit sharing, and collaborative delivery planning. Limited studies have considered the effects of integrating facility location and vehicle routing by addressing multiple goals in the design of a sustainable collaborative supply chain. We model the problem as a periodic two-echelon echelon-periodic location routing problem to integrate different decision levels. In order to investigate the trade-offs between the two opposing goals, a multi-objective approach is adopted. The Epsilon constraint method is used to generate a compromise between economic and ecological impacts. Cost and carbon emission sharing are assessed through the Shapley value mechanism. Furthermore, to determine the effect of parameter changes on the attained savings, a scenario analysis is performed. Results show the positive effect of collaboration among shippers and the importance of using integrated network design models. Environmental considerations in the pursuit of economic goals affect the gains produced and result in various transportation network structures. The performance of the coalition varies under different scenarios. Managerial implications are presented.

This paper describes how transport policy should not primarily concentrate on improving traffic, but rather on the activities that can be carried out with the help of transport and the needs that can be satisfied by those activities. The definition of concepts of basic needs and basic mobility is a normative task and changes over time and between regions. However, this definition is required to formulate concrete standards that guarantee the satisfaction of certain needs, the basic necessity of which is beyond dispute. The paper shows how these standards should describe opportunities provided by the transport and the spatial system as well as specific needs of certain groups of people. Accessibility standards are a suitable means of describing these components of basic mobility. The system of central locations is an appropriate basis for designing the spatial components of the standards system. It must be broken down into spatially low levels of centrality to guarantee the local supply of daily goods and services. The paper shows how standards are necessary for the system’s structure and the facilities of central locations. The paper discusses how the “Guidelines for Integrated Network Design” (RIN) are a successful example of designing transport components of such a system of accessibility standards. The RIN deal with the design of transport networks for public, private motorized, bicycle and pedestrian modes of transport.

DHL, an international air‐express courier, has been operating in Hong Kong for many years. In 1998, the new international airport located at a site considerably distant from the old location opened in Hong Kong (HK). Other airport‐related infrastructure facilities have also been developed or are being developed, resulting in major changes in transport structure as well as a shift in customer demand. In this paper a multiyear distribution network is designed for DHL(HK) using an integrated network design methodology, which consists of a macro model and a micro model. The macro model, a mixed 0–1 LP, determines in an aggregate manner the least‐cost distribution network. The micro model, a simulation, evaluates the operational viability and efficacy of the network according to its service coverage and service reliability. We also illustrate how coverage and reliability can be improved via the integrated use of the two models. Extensive discussion on relevant planning and operational issues of an air‐express courier are included. The methodology has been successfully implemented at DHL(HK). It has been used to design the network, to test strategic decisions, and to update the network.

Sustainable transport commonly considers either the interaction between built and natural environments or the interface between transportation and interdependent critical infrastructure. Although considering each of these key dimensions is a crucial task for achieving sustainable transport, the dimensions are infrequently considered together. When an integrated network design framework is proposed, two important issues are taken into account: ( a) the aftermath of potential severe weather episodes on metropolitan-area infrastructure and ( b) the existing interdependencies across transportation and fuel supply chain networks. Then the response of infrastructure in the face of flooding hazards is investigated. Framed within a multistage linear stochastic program, the proposed model seeks to find fueling station deployment that provides the transportation network with optimum random functionality when the network is stressed or under attack. A set of numerical experiments illustrates how changes to enhancement strategies at different stages of government affect the optimal investments in resilient design.

This paper discusses implementation issues concerning a telecommunications planning system for networks with hypothetical multimedia stochastic traffic. Stochasticity of the traffic and probabilistic statements about service commitment are captured by a chance-constrained stochastic programming formulation of the complex network dimensioning and traffic management problem treated in our previous work. Our approach involves a hierarchy of design objectives associated with the respective network layers. These are met by constituting a set of models – the Integrated Network Design System (INDS) – with common data, “solvers” and a graphical user interface (GUI) operating under the interactive control of the network planner.

Conductive hydrogels that simultaneously exhibit high mechanical robustness, reliable electrical conductivity, and interfacial adhesion are highly desirable for flexible sensing applications; however, achieving these properties in a single system remains challenging due to intrinsic structure-property trade-offs. Herein, a multifunctional conductive hydrogel (ASP hydrogel) is developed based on a polyacrylamide (PAM)/sodium alginate (SA) double-network architecture using a gallic acid (GA)-Fe3+-pyrrole (Py) coupling strategy. In this design, GA provides metal-coordination sites for Fe3+, while Fe3+ simultaneously serves as an oxidant to trigger the in situ polymerization of pyrrole, enabling the homogeneous integration of polypyrrole (PPy) conductive networks within the hydrogel matrix. The resulting ASP hydrogel exhibits a markedly enhanced fracture strength of 2.95 MPa compared with PAM (0.26 MPa) and PAM-SA (0.22 MPa) hydrogels, together with stable electrical conductivity and reproducible strain-dependent electrical responses. Moreover, the introduction of dynamic metal-phenolic coordination and hydrogen-bonding interactions endows the hydrogel with intrinsic self-healing capability and strong adhesion to diverse substrates. Rather than relying on simple filler incorporation, this work demonstrates an integrated network design that balances mechanical strength, conductivity, and adhesion, providing a versatile material platform for flexible strain sensors and wearable electronics.