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40-442: It is a hub and spoke system that meets downtown at Veterans Park (labeled as Center of NH on southbound departing lines) with one line departing from the nearby Canal Street Transportation Center. Service is generally limited to the city of Manchester, with a few lines extending into the neighboring towns of Bedford , Goffstown , Hooksett and Londonderry , and two express lines running to Concord and Nashua . Since July 2013,

80-462: A design process . Due to the free forms that naturally occur, the result is often difficult to manufacture. For that reason the result emerging from topology optimization is often fine-tuned for manufacturability. Adding constraints to the formulation in order to increase the manufacturability is an active field of research. In some cases results from topology optimization can be directly manufactured using additive manufacturing ; topology optimization

120-553: A bilateral security architecture in East Asia that is different from the multilateral security architecture in Europe. The US acts as a "hub", and Asian countries like South Korea and Japan are its "spokes". There is a strong connection between the hub and the spoke, but weak or no connections between the spokes themselves. In April 2014, all ten ASEAN defense chiefs and United States Secretary of Defense Chuck Hagel attended

160-478: A known analytical solution. There are various implementation methodologies that have been used to solve topology optimization problems. Solving topology optimization problems in a discrete sense is done by discretizing the design domain into finite elements. The material densities inside these elements are then treated as the problem variables. In this case material density of one indicates the presence of material, while zero indicates an absence of material. Owing to

200-419: A point-to-point network. For example, in a system with 6 destinations, the spoke–hub system requires only 5 routes to connect all destinations, and a true point-to-point system would require 15 routes. However distance traveled per route will necessarily be more than with a point-to-point system (except where the route happens to have no interchange). Therefore, efficiency may be reduced. Conversely, for

240-399: A problem is still infeasible owing to issues such as: Some techniques such as filtering based on image processing are currently being used to alleviate some of these issues. Although it seemed like this was purely a heuristic approach for a long time, theoretical connections to nonlocal elasticity have been made to support the physical sense of these methods. Fluid-structure-interaction

280-532: A public-private partnership with the New Hampshire Department of Transportation, were put together in 2018 by Kamen's company DEKA , proposing the name Millyard People Mover . The MTA has not yet allocated money for planning or studies as of 2021. Hub and spoke The spoke–hub distribution paradigm (also known as the hub-and-spoke system ) is a form of transport topology optimization in which traffic planners organize routes as

320-584: A result of this, spokes are simpler to operate, and so new routes can easily be created. In addition, the hub constitutes a bottleneck or single point of failure in the network. The total cargo capacity of the network is limited by the hub's capacity. Delays at the hub (such as from bad weather conditions) can result in delays throughout the network. Cargo must pass through the hub before reaching its destination and so require longer journeys than direct point-to-point trips. That may be desirable for freight, which can benefit from sorting and consolidating operations at

360-401: A series of " spokes " that connect outlying points to a central "hub". Simple forms of this distribution/connection model contrast with point-to-point transit systems, in which each point has a direct route to every other point, and which modeled the principal method of transporting passengers and freight until the 1970s. Delta Air Lines pioneered the spoke–hub distribution model in 1955, and

400-544: Is a strongly coupled phenomenon and concerns the interaction between a stationary or moving fluid and an elastic structure. Many engineering applications and natural phenomena are subject to fluid-structure-interaction and to take such effects into consideration is therefore critical in the design of many engineering applications. Topology optimisation for fluid structure interaction problems has been studied in e.g. references and. Design solutions solved for different Reynolds numbers are shown below. The design solutions depend on

440-405: Is in reality a cost factor, as we would not want to spend a lot of money on the material. To obtain the total material utilized, an integration of the selection field over the volume can be done. Finally the elasticity governing differential equations are plugged in so as to get the final problem statement. subject to: But, a straightforward implementation in the finite element framework of such

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480-418: Is optimized using either gradient-based mathematical programming techniques such as the optimality criteria algorithm and the method of moving asymptotes or non gradient-based algorithms such as genetic algorithms . Topology optimization has a wide range of applications in aerospace, mechanical, bio-chemical and civil engineering. Currently, engineers mostly use topology optimization at the concept level of

520-683: Is the public successor to Manchester's private bus service, which reached a peak annual ridership of 15.1 million in 1948, and the Manchester Street Railway that existed until 1940. The MTA was created by the City in May 1973, following requests by the private Manchester Transit bus provider for public subsidies. As of 2005, the MTA served an average of 1,905 riders each weekday, though ridership has grown since that time despite budget cutbacks by

560-455: Is thus a key part of design for additive manufacturing . A topology optimization problem can be written in the general form of an optimization problem as: The problem statement includes the following: Evaluating u ( ρ ) {\displaystyle \mathbf {u(\rho )} } often includes solving a differential equation. This is most commonly done using the finite element method since these equations do not have

600-439: The point-to-point model, requires fewer routes. For a network of n  nodes, only n − 1 routes are necessary to connect all nodes so the upper bound is n − 1 , and the complexity is O( n ). That compares favourably to the n ( n − 1 ) 2 {\displaystyle {\frac {n(n-1)}{2}}} routes, or O( n ), which would be required to connect each node to every other node in

640-483: The Green DASH and Concord Express, that are aimed at riders who might otherwise choose to drive. In addition to the 13 public transit routes, the MTA operates a StepSaver paratransit service and two free Shopper Shuttle routes that operate three days a week. Most MTA buses originate at Veterans Park in downtown Manchester. This is indicated on timetables and maps as Veterans Park, Downtown Radisson (a hotel in

680-526: The MTA has offered weekday service between Concord and Manchester-Boston Regional Airport , with most trips also stopping at the Center of NH hub in downtown Manchester, from 3:30 a.m. until 12:45 a.m. The neighboring suburb of Bedford contributed funding to the MTA until 2010, and service coverage was significantly reduced within the town the following year. As of 2009, 97% of Manchester residents lived within one-quarter mile of an MTA bus line. The MTA

720-572: The US–ASEAN Defense Forum in Hawaii. The meeting was the first time the US hosted the forum and was part of a US attempt to get the countries to strengthen military ties between themselves. Topology optimization Topology optimization is a mathematical method that optimizes material layout within a given design space, for a given set of loads , boundary conditions and constraints with

760-470: The airline industry was deregulated in 1978, several other airlines adopted Delta's hub-and-spoke paradigm. Airlines have extended the hub-and-spoke model in various ways. One method is to create additional hubs on a regional basis and to create major routes between them. That reduces the need to travel long distances between nodes near one another. Another method is to use focus cities to implement point-to-point service for high-traffic routes and to bypass

800-749: The attainable topological complexity of the design being dependent on the number of elements, a large number is preferred. Large numbers of finite elements increases the attainable topological complexity, but come at a cost. Firstly, solving the FEM system becomes more expensive. Secondly, algorithms that can handle a large number (several thousands of elements is not uncommon) of discrete variables with multiple constraints are unavailable. Moreover, they are impractically sensitive to parameter variations. In literature problems with up to 30000 variables have been reported. The earlier stated complexities with solving topology optimization problems using binary variables has caused

840-413: The buses were wrapped with historical images of Manchester. In an effort to boost ridership and publicize the service, the downtown circulator was rebranded as the Green DASH in 2011, and the buses were given a new, green color scheme that no longer obscures the windows and clearly marks them as a free loop bus. The free service is funded through a combination of federal grants and parking revenue. This marks

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880-437: The city and subsequent service cutbacks. Ridership in 2011 had increased 21% over 2004, growing from 382,979 to 462,109 total rides. Service peaked for the decade in 2009 with 531,961 rides before falling as a result of service cuts in 2010 and recovering slightly in 2011. The general trend during the period, however, has been a growth in ridership. In recent years, the MTA has sought to expand its ridership with new routes, such as

920-411: The community to search for other options. One is the modelling of the densities with continuous variables. The material densities can now also attain values between zero and one. Gradient based algorithms that handle large amounts of continuous variables and multiple constraints are available. But the material properties have to be modelled in a continuous setting. This is done through interpolation. One of

960-447: The concept revolutionized the transportation logistics industry after Federal Express demonstrated its value in the early 1970s. In the late 1970s the telecommunications and information technology sector subsequently adopted this distribution topology, dubbing it the star network network topology. "Hubbing" involves "the arrangement of a transportation network as a hub-and-spoke model". The hub-and-spoke model, as compared to

1000-786: The conversion of thermal energy into electric energy and the Peltier effect concerns the conversion of electric energy into thermal energy. By spatially distributing two thermoelectric materials in a two dimensional design space with a topology optimisation methodology, it is possible to exceed performance of the constitutive thermoelectric materials for thermoelectric coolers and thermoelectric generators . The current proliferation of 3D printer technology has allowed designers and engineers to use topology optimization techniques when designing new products. Topology optimization combined with 3D printing can result in less weight, improved structural performance and shortened design-to-manufacturing cycle. As

1040-406: The derivatives of the objective function are non-zero when the density becomes zero. The higher the penalisation factor, the more SIMP penalises the algorithm in the use of non-binary densities. Unfortunately, the penalisation parameter also introduces non-convexities. There are several commercial topology optimization software on the market. Most of them use topology optimization as a hint how

1080-435: The fluid flow with indicate that the coupling between the fluid and the structure is resolved in the design problems. Thermoelectricity is a multi-physic problem which concerns the interaction and coupling between electric and thermal energy in semi conducting materials. Thermoelectric energy conversion can be described by two separately identified effects: The Seebeck effect and the Peltier effect. The Seebeck effect concerns

1120-401: The goal of maximizing the performance of the system. Topology optimization is different from shape optimization and sizing optimization in the sense that the design can attain any shape within the design space, instead of dealing with predefined configurations. The conventional topology optimization formulation uses a finite element method (FEM) to evaluate the design performance. The design

1160-410: The hub entirely. The spoke–hub model is applicable to other forms of transportation as well: For passenger road transport , the spoke–hub model does not apply because drivers generally take the shortest or fastest route between two points. However, the road network as a whole likewise contains higher order roads like limited access highways and more local roads with most trips starting and ending at

1200-511: The hub, but it is problematic for time-critical cargo, as well as for passengers. The necessity of baggage transfers at the hub also increases the risk of missing luggage, as compared to the point-to-point model. In 1955, Delta Air Lines pioneered the hub-and-spoke system at its hub in Atlanta , Georgia , in an effort to compete with Eastern Air Lines . In the mid-1970s FedEx adopted the hub-and-spoke model for overnight package delivery. After

1240-661: The hub-and-spokes paradigm refers to the network of alliances the United States has built individually with other East Asian countries. The 1951 Security Treaty Between the United States and Japan , the 1953 U.S.–South Korea Status of Forces Agreement and the 1954 Mutual Defense Treaty between the United States and the Republic of China (later replaced by the Taiwan Relations Act ) are some examples of such bilateral security relationships. The system creates

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1280-430: The latter but spending most of the distance on the former. The hub-and-spoke model has also been used in economic geography theory to classify a particular type of industrial district. Economic geographer Ann Markusen theorized about industrial districts, with a number of key industrial firms and facilities acting as a hub, with associated businesses and suppliers benefiting from their presence and arranged around them like

1320-548: The material to the scalar selection field. The value of the penalisation parameter p {\displaystyle p} is generally taken between [ 1 , 3 ] {\displaystyle [1,\,3]} . This has been shown to confirm the micro-structure of the materials. In the SIMP method a lower bound on the Young's modulus is added, E 0 {\displaystyle E_{0}} , to make sure

1360-483: The most implemented interpolation methodologies is the Solid Isotropic Material with Penalisation method (SIMP). This interpolation is essentially a power law E = E 0 + ρ p ( E 1 − E 0 ) {\displaystyle E\;=\;E_{0}\,+\,\rho ^{p}(E_{1}-E_{0})} . It interpolates the Young's modulus of

1400-401: The optimal design should look like, and manual geometry re-construction is required. There are a few solutions which produce optimal designs ready for Additive Manufacturing. A stiff structure is one that has the least possible displacement when given certain set of boundary conditions. A global measure of the displacements is the strain energy (also called compliance ) of the structure under

1440-797: The park), or Center of NH (a convention center inside the hotel). Routes are organized into four zones. Zone 1 routes are standard fare local routes (routes 1 through 12), Zone 2 routes are intercity routes and require a day or month pass to ride (routes 21 and 22), Zone 3 routes are special excursions, and Zone 4 routes are free to ride. Dartmouth/VA Hospital Hanover St/E. Industrial Park Hanover St/E. Industrial Park Brown Ave/Airport Commerce Drive/Target SNHU/River Rd Bremer St/Mast Rd Bedford Grove Plaza/Second Street South Willow St/Mall of NH Elliot Hospital/E. Side Plaza Valley St/Mall of NH Front St/Hacket Hill Rd So. Beech St/Mall of NH Concord Zipline Nashua Zipline Green DASH Shopper Shuttle Originally,

1480-406: The prescribed boundary conditions. The lower the strain energy the higher the stiffness of the structure. So, the objective function of the problem is to minimize the strain energy. On a broad level, one can visualize that the more the material, the less the deflection as there will be more material to resist the loads. So, the optimization requires an opposing constraint, the volume constraint. This

1520-463: The same number of aircraft, having fewer routes to fly means each route can be flown more frequently and with higher capacity because the demand for passengers can be resourced from more than just one city (assuming the passengers are willing to change, which will of itself incur its own costs). Complicated operations, such as package sorting and accounting, can be carried out at the hub rather than at every node, and this leads to economies of scale . As

1560-546: The second attempt by the MTA at offering free transit downtown, following a fourteen-block free-ride zone that began in 1974 but has since been discontinued. Several groups in Manchester are currently advocating for the creation of a streetcar/rail system for the Downtown and Millyard areas. The idea was first raised in the early 1990s and was resurrected in 2012 when Dean Kamen proposed it. More concrete plans, proposing

1600-439: The spokes of a wheel. The chief characteristic of such hub-and-spoke industrial districts is the importance of one or more large companies, usually in one industrial sector, surrounded by smaller, associated businesses. Examples of cities with such districts include Seattle (where Boeing was founded), Silicon Valley (a high tech hub), and Toyota City , with Toyota . In the context of East Asian geopolitics, Victor Cha says

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