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Content available Evaluation of sinking effect in container stack
EN
The container yard is the key element of any modern container terminal. The huge amount of boxes dwelling on the operational areas of the terminals could occupy a lot of space, since one-time storage capacity of the container mega terminal handling over one million TEUs annually is something around 20 000 TEUs. The ecological pressure imposed on modern container terminal does not permit to allocate for this storage large land areas, thus forcing the box stacks grow high. The selection of the individual boxes becomes a complex and time-consuming procedure, demanding a lot of technological resources and deteriorating the service quality. The predicted combinatorial growth of redundant moves needed to clear the access to the individual container is aggravated by the well-known and widely discussed ‘sinking effect’, when containers arrived earlier are gradually covered by the ones arriving afterwards. While the random selection could be adequately assessed by combinatorial methods, the ‘sinking effect’ allows neither intuitive consideration, nor any traditional mathematical means. The only practical way to treat this problem today is in simulation, but the simulation itself causes yet another problem: the problem of model adequacy. This study deals with one possible approach to the problem designated to prove its validity and adequacy, without which the simulation has naught gnoseological value.
2
Content available Simulation Model of Container Land Terminals
EN
The simulation as a tool for the design of port and terminals has emerged as an answer for the demand to enhance the quality and reliability of the project results. Very high costs of the project solution implementation and practically total lack of liquidity of transport infrastructure objects always induced the immense commercial risks in the terminal business. Lately these risks have multiplied significantly due to rapid changes on the global and regional markets of transport services. Today, many experts come to see this volatility as an indicator of the next phase in development of the global trade system and the derivative cargo transportation system, specifically the state of temporal saturation. The shift of the global goods volumes from quick and steady growth to relatively small fluctuations around constant values causes quick oscillations in re-distribution of demand over the oversized supply. This new business and economic environment seriously affected the paradigm of transport terminal design and development techniques. The new operational environment of terminals put a request for the designers to arrange the results not in terms of “point”, but in terms of “functions”. Eventually it resulted in development of the modern object-oriented model approach. The wide spread of this approach witnesses the objective demand for this discipline, while in many aspects it remains in the intuitive (pre-paradigmal) phase of its development. The main reason for it is in the problem definition itself, which usually is formulated as the simulation of a given terminal. At the same time, the task is to assess the operational characteristics of the terminal engaged in processing of a given combination of cargo flows. Consequently, it is not the terminal that should be simulated, but the processes of cargo flows handling performed by this terminal under investigation. Another problem that restricts the practical spread of simulation is in the model adequacy. A model which adequacy is not proved has no gnoseological value at all. The paper describes the approach aimed at development of the models with the features discussed above.
EN
The terminology and conceptual apparatus of modern logistics as a scientific discipline is far from being shaped. Researches and developers of legislative and norm-setting documents are obliged to use their own or barrowed terminology, in both case not shared ubiquitously. Consequently, the interpretations even of basic concepts differ significantly. In particular, there exists an academic and practical point of view that refuse the right for existence of the term “transportation logistics”. This clause is explained by the proclaimed omnipresence and universality of logistics, which has in its operational glossary the term “transportation”, treated as a local, subordinated and thus secondary function. This paper tries to set a decisive rule to distinguish between general logistics and transportation logistics, arguing that these two disciplines are well separated by the objects and methodology, knowledge and activities. In transportation logistics defined this way the authors examine two principal components of the transportation processes, storage (warehousing) and movement (shipping). This consideration lead to conclusions that the classical mathematical toolkit is not fitted for the design and management of modern global supply chains.
EN
Current development of the maritime transportation system, namely fleet and ports specialization, growth of vessel sizes, rationalization of routs, trade regionalization etc., has made many traditional approaches and calculation techniques practiced for many long years in port design procedures to be inadequate and insufficient. A generally acknowledged tool for this task today is the simulation technique. In the same time, modern object oriented simulation approach provides usually only ad hoc solution for a project. It lacks the generality that was the main and natural feature of its traditional analytical predecessors. Very high time and labor consumption of simulation comes to a conflict with a very narrow scope of the resulting model’s application domain. This paper describes a new approach used to create a simulation tool for the port designers and planners combining the universality and generality of the analytical (so called “static”) methods with the efficiency and accuracy of the object-oriented simulation. The concept represented in the paper was implemented in the software product, which enabled to conduct experiments that proved the validity and adequacy of the model. The simulation tool was used in several sea port design project and now is a common instrument of several leading port design and consulting company in Russian Federation.
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