Logistics in Yemen: Identifying Demerits on Lack of Railways in Yemen

If one asks today whether Yemen can be extended by railway lines, it is natural to answer that the geographical nature of Yemen does not allow the extension of the railway line. It is surprising that the Ottoman Empire decided more than 100 years ago to complete this project, but the fall of the empire deprived Yemenis of this Great achievement. Under the title of establishing a modern network of railways for metals, goods and passengers, in recent years, practical steps have been taken to establish a railway network in Yemen and linking it to an international network of economic feasibility studies, but the railway project in Yemen is still just studies prepared by several companies. In 2013 there were talks between the Yemeni government and Russia, the outcome of the Yemeni-Russian talks committee was for the planning of the establishment of a local company in Yemen specializing in railways Under the supervision of the Russian leadership, a project that is the first of its kind as it aims to build an infrastructure. In this research paper the author attempt to use quantitative and qualitative research method, plan and execute fieldwork, collecting data from Competent ministerial bodies, ministry of transportation, Visit the specified area of the project) mineral wealth areas, coastal areas) etc. in Yemen, during fieldwork. Compile preliminary maps of the first alternative - Shahn / Aden and the second alternative - Muscat / Salalah / Sarfeet / Algheiza / Aden. During fieldwork and data collection, the author will visit ministry of transportation to meet the representative to get the requested data of the Proposed railway project along with Yemen land transportation affairs authority, then the author will visit designated area of the proposed project to meet the local authorities of each area to collect the data and discussing the main causes of the project's failure and delay along with that inspecting the security and services of the project’s designated area, although the government has conducted several studies on this project. After that the author will visit a the Minister of Transportation or a senior figure from the ministry for an interview to discuss the main challenges and constraints that causes the failure of the project and the delay to support the study, finally the author will visit Ministry of Public works and roads to collect preliminary maps of the International Coastal Railway (from Haradh to Shahn) and the economic feasibility study of the railway linking the mineral wealth areas (Al-Jouf and Marib Shabwa Balahaf). After analysing data and identifying findings that led to the projects failure, the author found three main challenges at present to build the railway project in Yemen are the absence of government economy, security and political stability

Model and Algorithm for Container Allocation Problem with Random Freight Demands in Synchromodal Transportation

This paper aims to investigate container allocation problem with random freight demands in synchromodal transportation network from container carriers’ perspective. Firstly, the problem is formulated as a stochastic integer programming model where the overall objective is to determine a container capacity allocation plan at operational level, so that the expected total transportation profit is maximized. Furthermore, by integrating simulated annealing with genetic algorithm, a problem-oriented hybrid algorithm with a novel gene encode method is designed to solve the optimization model. Some numerical experiments are carried out to demonstrate the effectiveness and efficiency of the proposed model and algorithm

Freight and passenger railway optimization

Das Ziel dieser Arbeit war es, einen Überblick über die aktuellen Beiträge der Literatur in den Bereichen der Eisenbahnlogistik sowohl im Güter- als auch im Personenverkehr zu geben. Während sich der Güterverkehr mit Problemen der Zusammenstellung der Züge und Waggons beziehungsweise der Verteilung der Leerfahrzeuge auseinander setzte, beschäftigte sich die Eisenbahnlogistik im Bereich des Personenverkehrs mit Optimierungsmodellen bezüglich Eisenbahnlinienplanung, Erstellung eines Fahrplanes, Inbetriebnahme von Fahrzeugen und Besatzungs- und Einsatzplanung. Die Bereiche der Eisenbahnlogistik haben in der Literatur eindeutig an Aufmerksamkeit gewonnen. In der Folge war es schwierig eine Auswahl aus dieser Vielfalt an Beiträgen zu treffen. Deshalb versucht diese Arbeit nur einen kurzen Einblick über einige wichtige Beiträge der letzten Jahre im Bereich der Eisenbahnlogistik zu geben. Aufgrund hochentwickelter mathematischer Techniken und deren Lösungsmöglichkeiten, die in den letzten Jahren aufgekommen sind, war es nun möglich die komplizierten Modelle der Eisenbahnlogistik in einer vernünftigen Zeit zu lösen. Darüber hinaus wurde ein Trend zur Entwicklung effizienterer entscheidungsunterstützender Hilfsprogramme für reale Gegebenheiten der Eisenbahnlogistik beobachtet. Im Großen und Ganzen sollten in Zukunft stärker integrierte Modelle der Eisenbahnplanung und Routenplanung entwickelt werden um robuste Lösungen und Methoden zu fördern.The aim of this work was to provide a survey of recent contributions about freight and passenger transportation. Whereas passenger optimization models considered problems such as line planning, train timetabling, platforming, rolling stock circulation, shunting and crew scheduling, freight transportation dealt with issues concerning car blocking, train makeup, routing, and empty car distribution. The field of rail transportation has clearly received attention resulting in a diversity of literature contribution. As it was difficult to handle the large amount of papers, this work is trying to give a short review of some important contributions made in recent years. Due to the increase in more sophisticated mathematical techniques, constant refinements in development of the models were made that were able to deal with larger problems. In addition, a trend towards more efficient transportation support systems was observed taking robustness into account. In addition, solution approaches that can deal with larger disturbances of the rail environment in a considerable speed and time, have received attention. Thus, future research can be done to develop more integrated models of scheduling and routing problems of train and passenger transportation to provide robust solutions and problem solving methods that handle disturbances of rail environment

Efficiency of the rail sections in Brazilian railway system, using TOPSIS and a genetic algorithm to analyse optimized scenarios

A railway system plays a significant role in countries with large territorial dimensions. The Brazilian rail cargo system (BRCS), however, is focused on solid bulk for export. This paper investigates the extreme performances of BRCS through a new hybrid model that combines TOPSIS with a genetic algorithm for estimating the weights in optimized scenarios. In a second stage, the significance of selected variables was assessed. The transport of any type of cargo, a centralized control of the operation, and sharing the railway track pushing competition, and the diversification of services are significant for high performance. Public strategies are discussed.Indisponível

Probabilistic and Fuzzy Approaches for Estimating the Life Cycle Costs of Buildings

The Life cycle cost (LCC) method makes it possible for the whole life performance of buildings and other structures to be optimized. The introduction of the idea of thinking in terms of a building life cycle resulted in the need to use appropriate tools and techniques for assessing and analyzing costs throughout the life cycle of the building. Traditionally, estimates of LCC have been calculated based on historical analysis of data and have used deterministic models. The concepts of probability theory can also be applied to life cycle costing, treating the costs and timings as a stochastic process. If any subjectivity is introduced into the estimates, then the uncertainty cannot be handled using the probability theory alone. The theory of fuzzy sets is a valuable tool for handling such uncertainties. In this Special Issue, a collection of 11 contributions provide an updated overview of the approaches for estimating the life cycle cost of buildings

A risk-informed approach to setting economically-justifiable maintenance strategies for railway tracks

The global railway infrastructure is carrying ever increasing amounts of railway and freight traffic which in turn is causing accelerated rates of infrastructure deterioration. Given the pressure to increase track utilization, the ageing infrastructure on which much of the railway transport systems are founded, and the constrained budgets under which the infrastructure is managed, appropriate maintenance needs to be predicted, prioritized, planned and carried out efficiently and economically. This doctoral research aims to develop a means of appraising railway track maintenance strategies economically while taking into account the associated risks and uncertainties. To this end, this research proposes, a Whole Life Cycle Cost Analysis (WLCCA) under uncertainty, while considering the direct and indirect costs of track maintenance, and the benefits to train operation, users, safety and the environment. The developed risk-informed approach is demonstrated via case studies on three different route types within the UK mainline railway network

An analysis of technical efficiency and service effectiveness for freight railways in African and European countries

For the past decades, technical efficiency and service effectiveness have become topical as performance measures in various sectors. However, a comparison of technical efficiency and service effectiveness for freight rail transport has received less attention in African and European countries. To address this challenge the current study seeks to analyse technical efficiency and service effectiveness of rail freight in African and European countries. Due to data unavailability in other countries, this study selected four African countries (South Africa, Morocco, Democratic Republic of Congo and Algeria) and four European countries (Lithuania, Austria, France and Germany). The data has been collected from the World Bank, International Union of Railway Statistics and Knoema for the period 2017. Input oriented and output oriented data envelope analysis (DEA) were used to analyze technical efficiency and service effectiveness, respectively. The application of DEA requires the selection of appropriate inputs, production and output variables. This study selected a number of employees and length of rail lines as input variables, gross train tonne kilometres (km) as production variable, tonnes carried and tonne kilometres (km) as output variables. The result shows that five out of eight countries were technical efficient and their services effective with values equal to 1.00. The Pearson correlation coefficient was used to analyse the relationship between technical efficiency and service effectiveness. The results indicate that there is a statistically significant positive correlation between technical efficiency and service effectiveness. To determine the impact exogenous variables on technical efficiency and service effectiveness, a Tobit regression analysis was conducted. The results show that technical efficiency and service effectiveness are not significantly affected by exogenous variables. On the other hand, technical efficiency is significantly affected by the number of employees while service effectiveness is significantly affected by gross train tonne km. This study recommends the use of less labour intensive assets and monitoring of gross train tonne km should be viewed as important strategies to improve technical efficiency and service effectiveness, respectively.Thesis (MCom) -- Faculty of Management and Commerce, 202