General Transport System Research Articles

Heuristic approximation and computational algorithms for closed networks: A case study in open-pit mining

We investigate a fundamental model from open-pit mining which is a cyclic system consisting of an (unreliable) shovel, trucks travelling loaded, unloading facility, and trucks travelling back empty. The interaction of these subsystems determines the mean number of trucks loaded per time unit — the capacity of the shovel, which is a fundamental quantity of interest. To determine this capacity we need the stationary probability that the shovel is idle. Because an exact analysis of the performance of the system is out of reach, besides of simulations there are various approximation algorithms proposed in the literature, which stem from computer science and can be characterized as general purpose algorithms.We propose for solving the special problem under mining conditions an extremely simple alternative algorithm. Comparison with several general purpose algorithms shows that for realistic situations in the open-pit mining application the special algorithm outperforms the precision of general purpose algorithms. This holds even if the general purpose algorithms incorporate more details of the underlying models than our simple algorithm, which is based on a strongly reduced model. The comparison and assessment is done with extensive simulations on a level of detail which the general purpose algorithms are able to cover.We discuss the application of our proposed algorithms to other applications. It turns out that our algorithms are analogues to Norton’s Theorem for a large class of general transportation systems.

Exploring critical attributes during air traffic congestion with a fuzzy DEMATEL\u2013ANP technique: a case study in Ninoy Aquino International Airport

The constant growth of air travel in the Philippines has brought about significant consequences to air traffic congestion. Given limited resources, major airports seek to address this issue while considering various attributes generally affecting air transportation. This paper adopts fuzzy decision-making trial and evaluation laboratory–analytic network process (DEMATEL–ANP) to identify the most critical attributes in the commercial aviation industry. A case study participated by key experts of Ninoy Aquino International Airport was conducted to illustrate the proposed approach. The fuzzy DEMATEL–ANP model performed satisfactorily as it was able to extract the global priority vectors of attributes under a fuzzy environment. The results showed that aviation safety is most prioritized, as can also be seen from the significant influence it brings on other attributes. Following next to safety in terms of priority are attributes that address the general air transportation system such as economic value, environmental value, social value, equitable treatment of competing airline, customer goodwill, and utilization of runway and terminal. Then, attributes relating to passenger cost, fuel cost, extra crew cost, landing/take-off fee, and cost of using flight routes are of last priority. Given the order of priorities and criticality of each attribute, short-term and long-term policies can be framed accordingly to propose air traffic flow management actions that can best address the issue on congestion.

An application of DEMATEL-ANP and PROMETHEE II approach for air traffic controllers’ workload stress problem: A case of Mactan Civil Aviation Authority of the Philippines

In the general air transportation system, air traffic controllers play a key role in maintaining a safe, orderly, and expeditious flow of air traffic. The fulfillment of this role is hindered as the complexity of controllers' workload aggravates due to various stressors. It is, therefore, the intention of this paper to address controllers’ workload stress problem by identifying the main stressors and arrive at an outranking of probable measures which can be applied at the earliest hint of such issue. The synergy of DEMATEL-ANP and PROMETHEE II approach is implemented to illustrate the decision-problem in a case study at Mactan Civil Aviation Authority of the Philippines (CAAP). The results revealed that the stressors presenting a significant contribution to the evidence of workload stress are attributed to the operational responsibilities of controllers. It then followed that compartmentalization outranked the other alternatives in reducing workload stress.

Formal Methods for Control of Traffic Flow: Automated Control Synthesis from Finite-State Transition Models

Today's increasingly populous cities require intelligent transportation systems that make efficient use of existing transportation infrastructure. However, inefficient traffic management is pervasive [1], [2], costing US$160 billion in the United States in 2015, including 6.9 billion h of additional travel time and 3.1 billion gal of wasted fuel [3]. To mitigate these costs, the next generation of transportation systems will include connected vehicles, connected infrastructure, and increased automation. In addition, these advances must coexist with legacy technology into the foreseeable future. This complexity makes the goal of improved mobility and safety even more daunting.

To the problem of dynamic modeling and management in an integrated environment of the industrial cluster

In this paper an approach to the problem of dynamic modeling and management in an integrated intellectual scientific, manufacturing, infrastructure, educational and social environment of the industrial cluster based on the structure of processes and mathematical processing of statistical data is discussed. The paper highlights methodology of clusters model constructing, quantitative estimates of individual enterprise opportunities, technological capabilities of the enterprise as a whole, the transition from the enterprise to the cluster. An important infrastructure investment project application for cluster enterprise general combined automobile cargo transportation system is considered.

Reduction Design of End Edge Effect in Stationary Discontinuous Armature PMLSM combined with Skewed Magnets and Stair Shape Auxiliary Teeth

Abstract – In recent years, a permanent magnet linear synchronous motor (PMLSM) has been used in various kinds of transportation applications for its relative high power density and efficiency. The general transportation system arranges the armature on the full length of transportation lines. However, when this method is applied to long distance transportation system, it causes increase of material cost and manufacturing time. Thus, in order to resolve this problem, we suggested stationary discontinuous armature PMLSM. However, the stationary discontinuous armature PMLSM contains the edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem because the cogging force that they exert bad influences the controllability of the motor. Therefore, in this paper we proposed the combination of skewed magnets and stair shape auxiliary teeth to reduce the force by edge effect. Moreover, we analyzed the influence of the design factors by using a 3-D finite element method (FEM) simulation tool.

전기자 분산배치 집중권 PMLSM의 전기자 간격에 따른 단부 코깅력 최소화

Currently, The general transportation system arranges the armature on the full length of transportation lines. However, when this method is applied to the long distance transportation system, it causes an increase of material cost and manufacturing time. Thus, in order to resolve this problem, discontinuous arrangement method of the armature has been proposed. However, in the method of using stationary discontinuous armatures, mover can stop in the freewheeling section which is non-installations section when disturbance is generated and the mover can not be moved because armature control is impossible. Thus, the distance determination of armature is very important. Also, when the armature is arranged discontinuously the edge always exists due to the structure. Due to this edge, the cogging force is greatly generated during the entry and ejection of the mover to the armature. This cogging force causes thrust force ripple generating noise, vibration and decline of performance, it must be reduced. Therefore, in this paper, we examined the end edge cogging force generated by the stationary discontinuous armatures through 2-D numerical analysis using finite element method (FEM) and we figured out distance of armature for end edge cogging force minimization.

Structure of the TatC core of the twin-arginine protein transport system

The twin-arginine translocation (Tat) pathway is one of two general protein transport systems found in the prokaryotic cytoplasmic membrane and is conserved in the thylakoid membrane of plant chloroplasts. The defining, and highly unusual, property of the Tat pathway is that it transports folded proteins, a task that must be achieved without allowing appreciable ion leakage across the membrane. The integral membrane TatC protein is the central component of the Tat pathway. TatC captures substrate proteins by binding their signal peptides. TatC then recruits TatA family proteins to form the active translocation complex. Here we report the crystal structure of TatC from the hyperthermophilic bacterium Aquifex aeolicus. This structure provides a molecular description of the core of the Tat translocation system and a framework for understanding the unique Tat transport mechanism.

Short-Term and Long-Term Feedstock Bio Jet Fuel for Green Environment of Air Transport in Climate Change Awareness

Air transportation and manageable cost is the key to determine the smooth running of the airlines. Today, the trend is changing with the environment generally and sustainability standards specifically. Responsibility towards environmental issues, in conjunction with safety and security, remains an essential promise for the aviation industry, even in the face of the economic downturn. IATA’s vision is for carbon-neutral growth on the way to a zero-emission future. This is being implemented through IATA’s four-pillar strategy: investing in technology, flying planes effectively, building efficient infrastructure and using positive economic measures (technology, operations, infrastructure and economic instruments). This paper will focus in the projection on biofuel as an alternative energy compromise reduction in carbon dioxide (CO2) emission in overview through short-term and long-term feedstock biomass. As environmental concerns are becoming clearer in general transportation systems, air transportation generates for its presence which must be considered in strategic planning development for the bio jet fuel to be implemented in near future in air transport operations for tenable greener skies.

New solutions for the general plan and transportation system in projects involving the modernization and reconstruction of steelmaking facilities

General principles and design innovations are discussed for the replacement of open-hearth shops by converter shops in projects undertaken to modernize and rebuild the steelmaking facilities of existing metallurgical plants

Traffic Flow Control using Neural Network

With rapid increase in motorization, urbanization, population growth, and changes in population density, Traffic Congestion problems have increased worldwide. Traffic Congestion causes increase in traveling time, air pollution and increase in fuel usage is also observed. Intelligent Transportation Systems (ITS) are used to avoid these problems and improve efficiency, safety and service. Traffic Flow Forecasting is an important part of ITS [1][2]. Traffic Flow Forecasting (TFF) is for Controlling Traffic and Intelligent Traffic Guidance. TFF is the study of interactions between vehicles, drivers, and infrastructure (which includes highways and traffic control devices), with the aim of understanding and developing an optimal road network with efficient movement of traffic and minimal traffic congestion problems. General Terms Intelligent Transportation System, Traffic Flow Forecasting, Neural Network.

Recent advances in the molecular biology of metazoan polyamine transport

Very limited molecular knowledge exists about the identity and protein components of the ubiquitous polyamine transporters found in animal cells. However, a number of reports have been published over the last 5 years on potential candidates for metazoan polyamine permeases. We review the available evidence on these putative polyamine permeases, as well as establish a useful "identikit picture" of the general polyamine transport system, based on its properties as found in a wide spectrum of mammalian cells. Any molecular candidate encoding a putative "general" polyamine permease should fit that provided portrait. The current models proposed for the mechanism of polyamine internalization in mammalian cells are also briefly reviewed.

Collaborative mobility: using geographic information science to cultivate cooperative transportation systems

It is increasingly clear that many of the existing transportation systems in the world are inefficient, inequitable and unsustainable. In many places, we have evolved a rigid transportation monoculture that forces people to adapt to the system rather than a flexible, responsive and user-friendly transportation polyculture that can adapt more easily to people and their activities. However, creating a flexible and responsive transportation system will require more coordination and cooperation across a variety of spatial scales and time horizons than is evident in our current, competitive systems. This lecture will discuss the role of collaboration in developing the next generation of transportation systems, and the role of geographic information science in facilitating cooperation across space and time for strategic, tactical and operational decision-making in transportation.

Towards Design Principles for Optimal Transport Networks

We investigate the navigation problem in lattices with long-range connections and subject to a cost constraint. Our network is built from a regular two-dimensional (d=2) square lattice to be improved by adding long-range connections (shortcuts) with probability P(ij) approximately r(ij)(-alpha), where r(ij) is the Manhattan distance between sites i and j, and alpha is a variable exponent. We introduce a cost constraint on the total length of the additional links and find optimal transport in the system for alpha=d+1 established here for d=1 and d=2. Remarkably, this condition remains optimal, regardless of the strategy used for navigation, being based on local or global knowledge of the network structure, in sharp contrast with the results obtained for unconstrained navigation using global or local information, where the optimal conditions are alpha=0 and alpha=d, respectively. The validity of our results is supported by data on the U.S. airport network.

TRANSPORTATION OF HAZARDOUS MATERIALS IN IRAN: A STRATEGIC APPROACH FOR DECREASING ACCIDENTS

“Hazardous materials” refer to those substances that seriously endanger human lives and/or the environment. The transportation of these materials will be inevitable in the increasingly industrialized economy of Iran. Nonetheless, numerous deadly accidents caused by the movement of these materials necessitate the design and implementation of preventive plans on several levels. This article looks into the present condition of transportation of hazardous materials in Iran and the resulting accidents. Optimal condition for the general transportation system of hazardous materials is delineated with due focus on transportation risk as the main parameter. Strategies for reaching the optimal condition are laid out and the impacts of these strategies on the reduction of accidents are analyzed.

Optimal transportation network with concave cost functions: Loop analysis and algorithms

Transportation networks play a vital role in modern societies. Structural optimization of a transportation system under a given set of constraints is an issue of great practical importance. For a general transportation system whose total cost C is determined by C = Sigma(i<j)C(ij)(I(ij)), with C(ij) (I(ij)) being the cost of the flow I(ij) between node i and node j, Banavar and co-workers [Phys. Rev. Lett. 84, 4745 (2000)] proved that the optimal network topology is a tree if C(ij) proportional |I(ij)|(gamma) with 0 < gamma < 1. The same conclusion also holds in the more general case where all the flow costs are strictly concave functions of the flow I(ij). To further understand the qualitative difference between systems with concave and convex cost functions, a loop analysis of transportation cost is performed in the present paper, and an alternative mathematical proof of the optimality of tree-formed networks is given. The simple intuitive picture of this proof then leads to an efficient global algorithm for the searching of optimal structures for a given transportation system with concave cost functions.

Validation Coverage for a Component-based SDL model of a Railway Signaling System

In this paper we present an application of formal verification techniques to a component-based SDL model of a railway signalling system lent by General Electric Transportation Systems. A MSC-driven validation technique has been applied to verify the multiple-configuration features of the system. This work addresses the problem of validating a component-oriented designed SDL model, with a partial reuse of previously verified MSC scenarios if a new component is introducing or modified: some possible solutions based on the coverage metrics and information provided by the adopted tools are discussed.

Models of freight transport system development

Abstract The article analyses the following issues: I) Basicfactors determining Transport system development;2) Transport system services and their assessment; 3) Goods handling Transport system as a research object. The objective of goods handling Transport system development and improvement is to estabhsh a general goods handlmg Transport system of the country ensuring satisfaction of national needs for high quality Transport service in this field; 4) Models of Transport modes interaction; 5) Determinate models for main Transport network development; 6) Model of development of private freight road Transport.

Relationship between Weibull and AMSAA models in reliability analysis

Historically, reliability of systems has been tracked based on a common assumption that, at the system level, the failure rate follows the exponential distribution, and is therefore assumed to be constant over the useful life of the system. However, this method, while adequate for many purposes, does not necessarily provide the early warning system that many companies need to stay ahead of expensive quality or reliability fixes. This paper presents a new method that provides the needed early warning, at a reasonable analysis cost, by combining the use of two reliability distributions for the purpose of analyzing fielded systems. In particular, this paper describes a hypothesized relationship between a key parameter contained in the Weibull distribution and within the Army Material Systems Analysis Activity (AMSAA) reliability growth model. Actual data from General Electric Transportation Systems (GETS) were used to explore this relationship. The results suggest that there indeed exists a significant relationship between the two models and both can be used in tandem to track reliability of systems.

Specific Fe2+ uptake system in strategy I plants inducible under Fe deficiency

The aim of this study was to examine more in detail the uptake of Fe2+ in non‐graminaceous (Strategy I plants) and graminaceous species (Strategy II plants). FeSO4 (2 μM) labelled with 59Fe was supplied in short‐term nutrient solution experiments (30 min, pH 5.0) to cucumber (Cucumis sativus L.), tomato (Lycopersicon esculentum Mill.), barley (Hordeum vulgare L.) and maize (Zea mays L.). A mutant of tomato (Tfer, defective in Fe deficiency inducible reductase) was also examined. Plant Fe nutritional status was modified by different Fe preculture (Fe adequate and Fe deficient, respectively). The Fe2+ uptake rates varied within a narrow range (0.25–0.40 μmol 59Fe g−1 root dry wt 30 min−1) in both, Strategy I and Strategy II plants adequately supplied with Fe. Under Fe deficiency, the Fe2+ uptake rates were markedly increased (4–10‐fold) in the Strategy I plants (tomato and cucumber). In contrast, in the graminaceous species (barley and maize) as well as in the Fe inefficient tomato mutant (Tfer), this increase was significantly less pronounced (1.3–1.6‐fold). Our results indicated that a Fe deficiency induced transport system for Fe2+ is operating in Strategy I plants. In the graminaceous species this inducible system is absent or is less expressed. The kinetic studies on Fe2+ uptake in cucumber plants gave indications for two saturable uptake systems that were activated under Fe deficiency, a high‐affinity system with a Km of 4.7±1.6 μM and Vmax of 7.5±1.9 μmol 59Fe g root dry−1 wt 30 min−1, and a low‐affinity system that operated at Fe2+ concentrations higher than 50 μM. Studies with cucumber plants on the specificity of the Fe deficiency activated high‐affinity Fe2+ transport system showed that a 10‐ and 100‐fold excess of Zn resulted in 42–83% inhibition of Fe2+ uptake, suggesting that Zn could also be transported by the Fe2+ transporter, although less efficiently. A lower inhibition of Fe2+ uptake was found in the control cucumber plants as well as in the control and Fe deficient barley plants at both Zn concentrations. Cadmium inhibited by 90% the Fe2+ uptake in Fe deficient cucumber plants that may be partly related to its toxicity. Fe2+ transport was markedly less affected (by 12%) in Fe deficient barley plants even at 100‐fold excess of Cd. In conclusion, it appears that Fe2+ is transported by an uptake system with distinct preference for Fe2+ (Fe2+ transporter) rather than by a general transport system for divalent cations.