Multiple Alternative Routes Research Articles

Access to medicines for rare diseases: A European regulatory roadmap for academia.

Background: Novel or repurposed medicines for rare diseases often emerge from fundamental research or empirical findings in academia. However, researchers may be insufficiently aware of the possibilities and requirements to bring novel medicinal treatment options to the patient. This paper aims to provide an easily applicable, comprehensive roadmap designed for academic researchers to make medicines for rare diseases available for patients by addressing the relevant regulatory frameworks, including marketing authorization and alternative routes. Methods: Key points of the regulatory chapters "Placing on the Market" and "Scope" of Directive 2001/83/EC relating to medicinal products for human use were summarized. Provisions in EU directives regarding blood products, radiopharmaceuticals, and herbal and homeopathic medicinal products were excluded. Cross-referencing to other provisions was included. European case-law was retrieved from the InfoCuria database to exemplify the implications of alternative routes. Results: Medicines may only be placed on the market with a valid marketing authorization. To obtain such authorization in Europe, a "Common Technical Document" comprising reports on quality and non-clinical and clinical studies must be submitted to a "competent authority", a national medicine agency or the European Medicines Agency. Timely interaction of academic researchers with regulators via scientific advice may lead to better regulatory alignment and subsequently a higher chance for approval of academic inventions. Furthermore, reimbursement by national payers could be essential to ensure patient access. Apart from the marketing authorization route, we identified multiple alternative routes to provide (early) access. These include off-label use, named-patient basis, compassionate use, pharmacy compounding, and hospital exemption for Advanced Therapy Medicinal Products. Discussion: Aligning academic (non-)clinical studies on rare diseases with regulatory and reimbursement requirements may facilitate fast and affordable access. Several alternative routes exist to provide (early) pharmaceutical care at a national level, but case-law demonstrates that alternative routes should be interpreted strictly and for exceptional situations only. Academics should be aware of these routes and their requirements to improve access to medicines for rare diseases.

Omicron Variant of SARS-CoV-2 Virus: In Silico Evaluation of the Possible Impact on People Affected by Diabetes Mellitus.

The Omicron variant of SARS-CoV-2 (Spike mutant B.1.1.529) carrying more than 30-point mutations in its structure, of which 15 are localized in the receptor-binding domain (RBD), allows to hypothesize a relevant change in interactivity with ACE2. In previous reports we hypothesized that the worse outcome of the COVID-19 disease in diabetes mellitus condition could be related to the non-enzymatic glycation of ACE2 receptor and an in silico evaluation led to the demonstration that the number of interactions is decreased in comparison to the unmodified model, possibly shifting the virus attack through different, multiple alternative entry routes. Given the evidenced features of this variant, we aimed to investigate with a computational approach the characteristics of Omicron SARS-CoV-2 with respect to its binding to human ACE-2 receptor, in a particular population, namely people affected by diabetes mellitus, at risk for unfavorable outcomes of the COVID-19. The computational analysis, considering the case in which all the lysine residues in the system are subjected to non-enzymatic glycation, confirmed that lysine glycation causes a general loss of interactivity between wild-type (WT)-Spike-RBD and ACE2. In the Omicron variant, Lys417 mutates into an asparagine, preventing the possible non-enzymatic glycation of this residue. Therefore, if non-enzymatic glycation seemed to cause a shift in the way in which the virus enters the cell from the ACE2-mediated mechanism to other pathways, in the case of the Omicron variant the ACE2-mediated approach of the virus seems to remain an important event to take into account. Indeed, interaction profile analysis, together with molecular mechanics–generalized Born surface area (MM-GBSA) calculations, suggests that the Omicron-Spike-RBD maintains a higher affinity for ACE2 subsequently to non-enzymatic glycation with respect to WT-Spike-RBD. The finding of the present computational study may suggest a different clinical relevance of the Omicron variant for the diabetes mellitus field, also in the possible direction of a lower severity of the disease.

In silico evaluation of the interaction between ACE2 and SARS-CoV-2 Spike protein in a hyperglycemic environment

The worse outcome of COVID-19 in people with diabetes mellitus could be related to the non-enzymatic glycation of human ACE2, leading to a more susceptible interaction with virus Spike protein. We aimed to evaluate, through a computational approach, the interaction between human ACE2 receptor and SARS-CoV-2 Spike protein under different conditions of hyperglycemic environment. A computational analysis was performed, based on the X-ray crystallographic structure of the Spike Receptor-Binding Domain (RBD)-ACE2 system. The possible scenarios of lysine aminoacid residues on surface transformed by glycation were considered: (1) on ACE2 receptor; (2) on Spike protein; (3) on both ACE2 receptor and Spike protein. In comparison to the native condition, the number of polar bonds (comprising both hydrogen bonds and salt bridges) in the poses considered are 10, 6, 6, and 4 for the states ACE2/Spike both native, ACE2 native/Spike glycated, ACE2 glycated/Spike native, ACE2/Spike both glycated, respectively. The analysis highlighted also how the number of non-polar contacts (in this case, van der Waals and aromatic interactions) significantly decreases when the lysine aminoacid residues undergo glycation. Following non-enzymatic glycation, the number of interactions between human ACE2 receptor and SARS-CoV-2 Spike protein is decreased in comparison to the unmodified model. The reduced affinity of the Spike protein for ACE2 receptor in case of non-enzymatic glycation may shift the virus to multiple alternative entry routes.

Candidate Sets for Alternative Routes in Road Networks (Extended Abstract)

We present a fast algorithm with preprocessing for computing multiple good alternative routes in road networks. Our approach is based on single via node routing on top of Contraction Hierarchies and achieves superior quality and efficiency compared to previous methods. The algorithm has neglectable memory overhead.

Adaptive specialization for spatial memory does not improve route efficiency: Comparing the ability of Clark's nutcrackers (Nucifraga columbiana) and pigeons (Columba livia) to solve traveling salesperson problems.

An important question in comparative cognition is whether animals are capable of planning ahead. Todd and Hills (Current Directions in Psychological Science, 29(3), 309-315, 2020) recently suggested that the ability to plan and choose internally may have scaffolded upon the cognitive mechanisms required by animals to search among patchy resources in their external environment. The traveling salesperson problem (TSP) is a spatial optimization problem in which a traveler is faced with the task of finding the best route from a start location to two or more destinations or targets. The Clark's nutcracker (Nucifraga columbiana) is a food-storing corvid with a highly specialized spatial memory. Spatial memory would appear to be deeply rooted in the cognitive mechanisms required for choosing efficiently among multiple alternative routes during a TSP. If so, then species like nutcrackers that are more dependent upon spatial memory for survival may have a greater ability to plan ahead or choose more efficiently among different route options than species that have less selective pressure for remembering the location of food, like pigeons. We examined the ability of nutcrackers to solve TSPs using the same procedures and target configurations as in our past research (Gibson, Wilkerson, & Kelly, Animal Cognition, 15, 379-391, 2012) to explore if nutcrackers can efficiently solve TSPs and how their route solutions compare with those of pigeons. Nutcrackers did not display an advantage in route efficiency and performed comparably to pigeons. Both species tended to prefer a nearest-neighbor strategy to more globally efficient routes. Having a more robust spatial memory may not improve the ability of animals to determine routes to multiple locations.

AN INTEGER LINEAR PROGRAMMING FORMULATION FOR POST-DEPARTURE AIR TRAFFIC FLOW MANAGEMENT

The air transportation domain faces issues in air traffic congestion which leads to delays affecting a network of flights. As stakeholders strive to address such issue by applying air traffic flow management (ATFM) actions, there exists an apparent divide in the solution objective and perspectives. In the extant literature, solution approaches involving ATFM actions are often framed from the perspective of only one stakeholder to another. Such a scheme does not comprehensively cover the overall goal of the stakeholders, thus, provides inadequate, even conflicting, solutions. Therefore, this paper proposes an integer linear programming model for a rerouting problem that satisfactorily incorporates the individual interests of stakeholders (i.e., airport management, airline sector, air traffic management) in the commercial aviation industry and the common goal of ensuring safety in flight operations. The proposed model is designed to tactically select an alternate route when the primary route is constrained due to uncertainties such as inclement weather in a post-departure scenario. A hypothetical case study involving multiple destinations and alternate routes is carried out to illustrate the validity of the model. A Demo version of Lingo software is used to run the proposed model. Notable computational results show significant differences of selected routes as individual system interests are taken into isolation compared to when the general, collaborative model is implemented. In other words, the proposed model is able to show that preferences in alternate routes do vary with the individual interests of stakeholders, more so with the integration of the collaborative decision among stakeholders. Therefore, this research work provides a groundwork to a more comprehensive take of managing air traffic scenario involving all phases of flights. This is realized by providing a proof that significant shifts of decision solutions occur when the overall goal of stakeholders is considered rather than taking their individual interests into isolation.

VCS: A method of in-order packet delivery for adaptive NoC routing

Adaptive routing proves its efficiency in sustaining higher network performance bypassing packets through alternate congestion-free minimal or non-minimal routes for a many-core on-chip communication system. It prevents the network from reaching an early saturation due to the stalling of packets in the priority-fixed shortest route for a longer period. However, routing packets adaptively to an alternate route instead of choosing the priority-fixed and shortest route may lead to an unintended state of delivering packets out-of-order sequence at the destination node that is not accepted by many message-passing systems. This ordering mismatch is due to allowing multiple alternate routes for packets of the same communication flow in adaptive mode. In such a case, a packet with a higher sequence number takes over another packet of the same communication flow having a lower sequence number. Storing and reordering all unordered packets of the same communication flow at the sink side becomes costlier due to the increasing area and power requirement. Ideally, the added memory size reaches to infinity for storing all unordered packets that belong to the same communication flow. In the proposed method, we guarantee delivery of all packets belongs to the same communication flow in an orderly manner under adaptive routing mode. In particular, we have proposed a flow-control policy based on a virtual circuit switch (VCS) method that exclusively won and reserve a virtual path for routing packets in an adaptive mode for each communication flow. To maximize network performance, we allow sharing of the reserved path among packets of different communication flows, routing under priority fix deterministic mode. The method saves need of having additional memory unit for storing all unordered packets while guaranteeing the packet’s ordering sequence at the destination end. An experiment conducted on two different size Mesh networks (8x8 and 12x12) under several synthetic traffic and benchmark application reveals that our virtual circuit switching (VCS) based proposed method offers a significant improvement over the state-of-the-art packet reordering method (ROR) and two similar type of research works. Our simulation based experimental result shows that method offers a 60% higher saturation point and 21% improvements (maximum) in throughput while offering a reduction of 60% in NoC area and 58% power value compared to the baseline reorder (ROR) method.

Heuristic Optimization for Robust Resource-Constrained Flexible Project Scheduling Problem

In this article, we studied a robust resource constrained flexible project scheduling problem (RRCFPSP), in which the activity duration is an uncertain number and each activity may have multiple alternative execution routes. We represent RRCFPSP by an AND/OR network and propose a mathematical formulation. Moreover, optimal solution can be reached when the duration of each activity takes the maximum value. To employ the heuristic algorithms which specialise in solving continuous problems to solve the considered problem effectively, we develop a novel float weight optimization frame (FWOF). By combining this frame with particle swarm optimization (PSO), gravity search algorithm (GSA) and whale optimization algorithm (WOA), we propose three algorithms FPSO, FGSA and FWOA respectively. Finally, we design a series of numerical experiments, and experimental results show that the FWOF can make traditional certain heuristic algorithms solve the problems we consider effectively and accurately, especially in large-scale cases.

Metabolic route computation in organism communities

BackgroundMicrobiomes are complex aggregates of organisms, each of which has its own extensive metabolic network. A variety of metabolites are exchanged between the microbes. The challenge we address is understanding the overall metabolic capabilities of a microbiome: through what series of metabolic transformations can a microbiome convert a starting compound to an ending compound?ResultsWe developed an efficient software tool to search for metabolic routes that include metabolic reactions from multiple organisms. The metabolic network for each organism is obtained from BioCyc, where the network was inferred from the annotated genome. The tool searches for optimal metabolic routes that minimize the number of reactions in each route, maximize the number of atoms conserved between the starting and ending compounds, and minimize the number of organism switches. The tool pre-computes the reaction sets found in each organism from BioCyc to facilitate fast computation of the reactions defined in a researcher-specified organism set. The generated routes are depicted graphically, and for each reaction in a route, the tool lists the organisms that can catalyze that reaction.We present solutions for three route-finding problems in the human gut microbiome: (1) production of indoxyl sulfate, (2) production of trimethylamine N-oxide (TMAO), and (3) synthesis and degradation of autoinducers. The optimal routes computed by our multi-organism route-search (MORS) tool for indoxyl sulfate and TMAO were the same as routes reported in the literature.ConclusionsOur tool quickly found plausible routes for the discussed multi-organism route-finding problems. The routes shed light on how diverse organisms cooperate to perform multi-step metabolic transformations. Our tool enables scientists to consider multiple alternative routes and identifies the organisms responsible for each reaction.

Traffic flow estimation on the expressway network using toll ticket data

Traffic flow estimation (TFE) is an important task for intelligent transportation systems, especially for expressway system in travel demand management, road conditions monitor etc. Traffic flow is usually detected by fixed sensors, which is neither practical nor economically feasible to cover all expressway component links. Additionally, the existing research usually ignores the effects of drivers’ dwell behaviours on TFE. To fill these gaps, this study proposes a TFE method based on toll ticket data (TTD) which records trip information, except the actual route. Meanwhile, dwell time, as a key component of drivers’ journeys, will be integrated into the proposed approach. In this study, a Gaussian mixture model for the origin–destination pairs with multiple alternative routes will be formulated. Moreover, expectation–maximisation algorithm is introduced to estimate link traffic flows and dwell time distributions simultaneously. By TTD collected from the Shandong Province Expressway in China, the proposed approach is calibrated and applied to TFE empirically. The results show that the proposed approach has a good performance on TFE with consideration of dwell time.

Modes of Transmission of Zika Virus.

For >60 years, Zika virus (ZIKV) has been recognized as an arthropod-borne virus with Aedes species mosquitoes as the primary vector. However in the past 10 years, multiple alternative routes of ZIKV transmission have been identified. We review the available data on vector and non-vector-borne modes of transmission and interventions undertaken, to date, to reduce the risk of human infection through these routes. Although much has been learned during the outbreak in the Americas on the underlying mechanisms and pathogenesis of non-vector-borne ZIKV infections, significant gaps remain in our understanding of the relative incidence of, and risk from, these modes compared to mosquito transmission. Additional research is urgently needed on the risk, pathogenesis, and effectiveness of measures to mitigate non-vector-borne ZIKV transmission.

Deep functional analysis of synII, a 770-kilobase synthetic yeast chromosome

Here, we report the successful design, construction, and characterization of a 770-kilobase synthetic yeast chromosome II (synII). Our study incorporates characterization at multiple levels-including phenomics, transcriptomics, proteomics, chromosome segregation, and replication analysis-to provide a thorough and comprehensive analysis of a synthetic chromosome. Our Trans-Omics analyses reveal a modest but potentially relevant pervasive up-regulation of translational machinery observed in synII, mainly caused by the deletion of 13 transfer RNAs. By both complementation assays and SCRaMbLE (synthetic chromosome rearrangement and modification by loxP-mediated evolution), we targeted and debugged the origin of a growth defect at 37°C in glycerol medium, which is related to misregulation of the high-osmolarity glycerol response. Despite the subtle differences, the synII strain shows highly consistent biological processes comparable to the native strain.

Energy Conscious based Multipath Routing Algorithm in WSN

Wireless Sensor Network (WSN) is a collection of sensory nodes forming a provisional network without the assistance of any recognized infrastructure. Due to the minimal range of each node's transmissions, it may be essential for one sensory node to request for the aid of other sensory node in transferring a packet between the source and sink. The important issue while designing WSN is the routing protocol that makes the best use of the severely minimal resource, especially the energy consumption. We propose a Energy Conscious multipath Routing Algorithm designed to improve the latency, resiliency and efficiency through discovering multiple routes between the source and sink. A Sink Originated Route Discovery (SORD) process provides the locality information of the source to the sink. One dominant and multiple alternate routes are generated at the end of the route discovering process. Apart from the dominant route, all the other nodes are put to sleep mode in order to conserve energy and create a concussion free route. Data is transmitted between the source and sink through the dominant route and if there is a disturbance in the existing route, the next preferred alternate route is used. If the route doesn't exist between the source and sink, the process starts from the beginning. Further, we analyze how the proposed protocol overcomes the drawback of the existing protocols. This system is implemented by using NS-2.34. By altering route update guidelines of existing on-demand routing schemes the Performance gains in the order of 10-15 % could be achieved. The simulation results show that the proposed protocol has less control packet overhead, less average energy consumption and the algorithm is faster.

Hydrogen Sulfide Measurement With Wireless Technology

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 171720, “H2S Measurement Using Wireless Technology,” by P. Phelan, A.-R. Shames Khouri, and H.A. Wahed, Abu Dhabi Gas Industries, prepared for the 2014 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 10–13 November. The paper has not been peer reviewed. Hydrogen sulfide (H2S) represents a major hazard in oil and gas production, and the efficient and reliable detection of gas leaks is a critical safety aspect. Wireless-detection systems offer an opportunity to expand the measurement area. This paper reviews a specific application of wireless technology in gas detection and details the steps taken to assess the integrity of the wireless system and the considerations necessary to ensure the reliability and availability of the signal transmission. Wireless-Sensor Networks (WSNs) WSNs are an alternative to hard-wired systems where the cabling is replaced by radio-frequency (RF) transmission of the measured data into a host system. The network may be point-to-point or meshed transmission. Meshed transmission allows for multiple alternative routes and, therefore, offers potential improvements in the ability of the system to ensure that the data are delivered to the host system. WSNs have been developed since 2003 on the basis of Institute of Electrical and Electronics Engineers (IEEE) Standard 802.15.4, which defines the operating frequency of 2.4 GHz and other aspects of the basic physical layer of communication. This is currently adopted by the process industry as the essential foundation for most wireless-measurement systems. Subsequent to the definition of the physical layer for communication, the HART Foundation, which was originally established to define protocols for serial data communication between cabled field devices, was extended to cover WSN technology. This wireless HART technology was subsequently approved by the International Electrotechnical Commission (IEC) in 2006 as IEC Standard 62591. A parallel development was undertaken by the International Society of Automation (ISA) in the US under the ISA 100.11a standard in 2009. Each of these standards seeks to establish interoperability of the different equipment manufacturers, and it is important that this convergence be achieved to prevent development and adoption delays. The development of battery technology is also an important aspect of WSNs. Significant advances in battery design, solar-cell charging, and energy harvesting are expected to play an active role in the future. In present systems, sophisticated software is used to turn on and wake up components to minimize power consumption. It is also imperative that monitoring of battery status be managed actively by the host system.

Neighborhood environmental attributes and adults' maintenance of regular walking.

Environmental initiatives to support walking are keys to noncommunicable disease prevention, but the relevant evidence comes mainly from cross-sectional studies. We examined neighborhood environmental attributes associated cross-sectionally with walking and those associated prospectively with walking maintenance. Data were from the Australian Diabetes, Obesity and Lifestyle study collected in 2004-2005 (baseline) and in 2011-2012 (follow-up). Participants who did not move residence during the study period (n = 2684, age range: 30-77 yr at baseline) were categorized as regular walkers (walked five times per week or more) or not at baseline. Regular walkers were divided into those who stopped and those who maintained regular walking at follow-up. Regression analyses examined relationships of regular walking and walking maintenance with perceived attributes of neighborhood destinations and pedestrian environments. Regular walking at baseline was significantly associated with availability of shops (odds ratio [OR] = 1.13, 95% confidence interval [CI] = 1.04-1.22), many alternative routes (OR = 1.12, 95% CI = 1.01-1.23), park or nature reserve (OR = 1.13, 95% CI = 1.02-1.26), bicycle or walking tracks (OR = 1.08, 95% CI = 1.00-1.17), and feeling safe to walk (OR = 1.18, 95% CI = 1.01-1.38). Maintenance of regular walking was associated with the availability of multiple alternative routes (OR = 1.19, 95% CI = 1.03-1.38). Having many alternative routes and walking tracks was associated with walking maintenance among those who were not or had stopped working. Neighborhood destinations (shops and parks) and pedestrian environments (alternative routes, walking trails, and safety from crime) were found to be associated with regular walking, but only pedestrian environment attributes were found to be related to the maintenance of regular walking. Further evidence from prospective studies is required to identify other neighborhood environmental attributes that might support walking maintenance.

Induced mutations in yeast cell populations adapting to an unforeseen challenge.

The modern evolutionary synthesis assumes that mutations occur at random, independently of the environment in which they confer an advantage. However, there are indications that cells facing challenging conditions can adapt rapidly, utilizing processes beyond selection of pre-existing genetic variation. Here, we show that a strong regulatory challenge can induce mutations in many independent yeast cells, in the absence of general mutagenesis. Whole genome sequencing of cell lineages reveals a repertoire of independent mutations within a single lineage that arose only after the cells were exposed to the challenging environment, while other cells in the same lineage adapted without any mutation in their genomes. Thus, our experiments uncovered multiple alternative routes for heritable adaptation that were all induced in the same lineage during a short time period. Our results demonstrate the existence of adaptation mechanisms beyond random mutation, suggesting a tight connection between physiological and genetic processes.

A Driven Backup Routing Table to Find Alternative Disjoint Path in Ad Hoc Wireless

The performances of the routing protocols are important since they compute the primary path between source and destination. In addition, routing protocols need to detect failure within a short period of time when nodes move to start updating the routing table in order to find a new primary path to the destination. Meantime, loss of packets and end-to- end delays will increase thereby reducing throughput and degrading the performance of the network. This paper proposes a new algorithm, DBRT (Driven Backup Routing Table), to improve the existing proactive protocols such as DSDV (Destination Sequenced Distance Vector) protocol by creating a backup routing table to provide multiple alternative routes. The DBRT algorithm identifies adjacent nodes for each node in the same range and then selects one of these as a backup next hop according to the available path to the destination. The results show that loss of data packets, throughput and end-to-end delay times between source and destination are improved. The results show that the new protocol does not degrade the network’s performance despite sending extra messages to construct and update the new backup routing table. Simulations (using an NS2 simulator) are undertaken to demonstrate the difference between using a DSDV protocol with or without the proposed schema.

Multi-criteria, personalized route planning using quantifier-guided ordered weighted averaging operators

This paper presents a generic model for using different decision strategies in multi-criteria, personalized route planning. Some researchers have considered user preferences in navigation systems. However, these prior studies typically employed a high tradeoff decision strategy, which used a weighted linear aggregation rule, and neglected other decision strategies. The proposed model integrates a pairwise comparison method and quantifier-guided ordered weighted averaging (OWA) aggregation operators to form a personalized route planning method that incorporates different decision strategies. The model can be used to calculate the impedance of each link regarding user preferences in terms of the route criteria, criteria importance and the selected decision strategy. Regarding the decision strategy, the calculated impedance lies between aggregations that use a logical “and” (which requires all the criteria to be satisfied) and a logical “or” (which requires at least one criterion to be satisfied). The calculated impedance also includes taking the average of the criteria scores. The model results in multiple alternative routes, which apply different decision strategies and provide users with the flexibility to select one of them en-route based on the real world situation. The model also defines the robust personalized route under different decision strategies. The influence of different decision strategies on the results are investigated in an illustrative example. This model is implemented in a web-based geographical information system (GIS) for Isfahan in Iran and verified in a tourist routing scenario. The results demonstrated, in real world situations, the validity of the route planning carried out in the model.

Adaptive alternate routing in WDM networks and its performance tradeoffs in the presence of wavelength converters

Routing in wavelength-routed all-optical WDM networks has received much attention in the past decade, for which fixed and dynamic routing methods have been proposed. Taking into account the observation that wavelength-routed all-optical WDM networks are similar to circuit-switched voice networks, except with regard to wavelength conversion, we propose an adaptive alternate routing (AAR) scheme for wavelength-routed all-optical WDM networks. A major benefit of AAR is that it can operate and adapt without requiring an exchange of network status, i.e., it is an information-less adaptive routing scheme. The scope of this work is to understand this scheme in its own right since no other dynamic routing schemes are known to have the information-less property. In this paper, we conduct a systematic study of AAR with regard to factors such as the number of converters, load conditions, traffic patterns, network topologies, and the number of alternate paths considered. We observe that the routing scheme with multiple alternate routes provides more gain at a lower load instead of requiring any nodes to be equipped with wavelength converters. On the other hand, the availability of wavelength converters at some nodes, along with adaptive routing, is beneficial at a moderate to high load without requiring all nodes to be equipped with wavelength converters. We also observed that a small number of alternate routes considered in a network without wavelength converters gives a much better performance than a network with full wavelength converters and fewer alternate routes. Throughout this study, we observed that the proposed adaptive alternate routing scheme adapts well to the network traffic condition.

Simultaneous Optimization of Storage Allocation and Routing Problems for Belt-conveyor Transportation

Raw materials for industrial steel-making plants need to be stored in material yards in order to satisfy various production requirements. The stored materials are supplied to production plants by belt-conveyors with multiple alternative transportation routes. The simultaneous optimization of the storage allocation and transportation routing for the raw materials yard is required for achieving production that is flexible to changes in demand. In this paper, we propose a Lagrangian decomposition and coordination approach for storage allocation and routing for a belt-conveyor transportation system to handle demand changes. The overall problem is decomposed into an allocation planning subproblem and a transportation routing subproblem. A near-optimal solution for allocation planning and transportation routing is derived by repeating each optimization of subproblems and multiplier updates. The effectiveness of the proposed approach is confirmed in numerical experiments.