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Reprezentacja wiedzy w komputerowo wspomaganym systemie identyfikacji obszaru zagrożenia dla operatora w siłowni okrętowej.

Podsiadło A., Tarełko W.

Zagadnienia Eksploatacji Maszyn

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2007

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Vol. 42, nr 1

157-171

PL

W artykule przedstawiono metodę rozwiązania decyzyjnego problemu identyfikacji elementów obszaru zagrożenia dla operatora w siłowni okrętowej z wykorzystaniem tzw. modelu bazowego nazywanego reprezentacją wiedzy. W tym celu sformułowano problem decyzyjny, zaprezentowano algorytm jego rozwiązania oraz uczestników procesu rozwiązania problemu (ekspert, projektant systemu, komputer) i ich zadania. Do budowy modelu bazowego wykorzystano dwa sposoby reprezentacji wiedzy o procesie identyfikacji elementów obszaru zagrożenia: reprezentację logiczną w postaci relacyjnej bazy wiedzy oraz reprezentację strukturalną w postaci grafów.

EN

Ship power plants have to accomplish requirements of future users, i.e. a machinery crew. As a rule, these requirements are formulated in the form of a set of ship power plant properties that are realized at various stages of the product life-cycle. These properties of ship power plants are 'built-in' at the development stage of a design process. In order to achieve the desired levels of the selected properties, designers should take into account many various design principles. One of the general design principles is 'design for safety'. It means that the ship power plant has to meet requirements of the safety. One of the possible solutions for increasing the operator's safety is to build a computer-aided system supporting design process of safe ship power plants. Such a system is being developed in Gdynia Maritime University. This paper deals with the computer-aided system for hazard zone identification in ship power plants. In every procedure involving identification actions, we could observe that one of the typical multiple recurrent activities is an act of deciding. It is obvious that such an activity should be preceded by appropriate actions preparing this decision. For enabling an appropriate course of these actions, we should constitute an appropriate framework, for example in the form of a decisions-making system. In our approach, all decision-making problems are solved by means of a base model called knowledge representation. The base model uses the following ways of knowledge representation concerning the process of hazard zone identification: - logical representation in the form of the relative knowledge base, - structural representation in the form of the graphs. Both kinds of the mentioned knowledge are stored in the knowledge base of the computer-aided system for hazard zone identification in ship power plants. Realization of a decision-making process for hazard zone identification requires the development of an appropriate procedure. This procedure is realized in such a way that a system user, using the knowledge base and taking the internal and external restrictions into account, determines its stages by attributing the special comparative values worked out. In this way, the user makes a decision concerning the degree of hazard for operators within the identified hazard zone. Thus, this decision-making procedure consists of carrying out the selection of dangerous or harmful factors and their values (input variable values), which could trigger off any consequences for operators (output variable values). Based on these determined values, the system should calculate a value of an index expressing influence of dangerous and harmful factors on hazards for operators. In depend on the received value, the system proposes a proper strategy of safety design for the selected hazard situation element, for instance: - withdrawing operators to more safe places by means of replacing a machinery component together with operations to be involved, - decreasing hazards for operators by selecting suitable design features of machinery components which can reduce influence of dangerous and harmful factors, - remaining the considered design solution without any changes. An algorithm of generating solution for the hazard zone identification task in a ship power plant completes the description of the knowledge representation in computer-aided system for hazard zone identification for operators of ship power plants.

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System identyfikacji obszaru zagrożenia dla operatora w siłowni okrętowej.

Podsiadło A., Tarełko W.

Zagadnienia Eksploatacji Maszyn

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2006

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Vol. 41, nr 3

143-158

PL

Ze względu na specyfikę siłowni okrętowej, w zasadzie każde jej miejsce może być bardziej lub mniej niebezpieczne dla operatorów, wykonujących określone czynności eksploatacyjne. Z tego względu celowe jest opracowanie metody umożliwiającej, już w początkowych etapach projektowania siłowni, wskazanie tych miejsc, które stwarzają potencjalnie największe zagrożenia dla operatorów. W artykule zaprezentowano system identyfikacji obszaru zagrożenia dla operatora będący modułem komputerowo wspomaganego systemu projektowania bezpiecznych siłowni okrętowych, który od kilku lat budowany jest w Akademii Morskiej w Gdyni. Identyfikację obszaru zagrożenia przeprowadza się w oparciu o informacje, dotyczące struktury i funkcji węzłów konstrukcyjnych siłowni, zawarte w jej projekcie wstępnym. Informacje te poparte wiedzą pozyskaną od ekspertów w dziedzinie projektowania i eksploatacji siłowni okrętowych umożliwiają określenie miejsc i sytuacji niebezpiecznych dla operatora. Jako narzędzie realizacji systemu komputerowego identyfikacji obszaru zagrożenia wybrano język sztucznej inteligencji PROLOG LPA.

EN

The development of our civilization allows us to produce new machines, installations, and plants that unfortunately can trigger off any kind of hazards for the safety of community. Large means of transport, power and chemical plants are numbered among the most dangerous ones. From this point of view, ships are specific technical systems with possible types of hazards such as: fire, explosion, accidents, flooding, etc. Moreover, the most dangerous ship spaces are their power plants. Due to their unreliability, two types of danger could appear: - for operators carrying out any kind of operational or maintenance activities with ship machinery (death or human body injury), - for marine transport or environment (ship accidents or undesirable sea pollution). The specifity of ship power plants allows us to assert that all their spaces can be more or less dangerous for operators carrying out any operations. For this reason, the ship power plants should be well-designed to minimize the possible hazards for their operators. The complexity of modern ship power plants and the increased requirements concerning the operator's safety contest the conventional design methods. One of possible ways of solving this problem is providing to the designers appropriate tools, which allow them to consider the operator's safety during a design process, especially at its large stages. A computer-aided system supporting design of safe ship power plants could be such a tool. This concept has been realized in a computer-aided system supporting the design process of safe ship power plants. Such a system has been developing at the Gdynia Maritime University. It consists of two main modules: - a system of hazard zones identification in ship power plants on a base of their preliminary design, - an expert system aiding design of the most dangerous zones from the safety point of view. This paper deals with the first module that is the computer-aided system for hazard zone identification in ship power plants. Cooperation between a designer and a computer sets up an idea of such a system, in which: - the designer makes proper decisions based on his knowledge, intuition, experience and analysis of the preliminary design documentation, - the computer provides information sets, converts data, and checks correctness of the designer's decisions. The computer-aided system for hazard zone identification in ship power plants allows designers of ship power plants to: - determine hazard situations and spaces in a ship power plant, - assess the influence of dangerous and harmful factors on potential hazards for operators, - receive information allowing designers to choose the appropriate design strategy. Particularly, sources of information for identification, basic terms concerning identification of hazard zone and identification procedure of hazard zone are presented in this paper. Moreover, it also contains a working principle of a computer-aided system for hazard zone identification. Computer screens illustrating: the selection of the operational or maintenance tasks; the selection of ship machinery items and the assessment of a procedure; the selection of ship machinery component and operational or maintenace acivities; the assessment of the selected ship machinery component and the assessment value of the influence of dangerous and harmful factors on potential hazard for operators compete description of the mentioned system.

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Modelowanie procesu podejmowania decyzji w systemie identyfikacji obszaru zagrożenia dla operatora w siłowni okrętowej.

Podsiadło A., Tarełko W.

Zagadnienia Eksploatacji Maszyn

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2006

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Vol. 41, nr 4

131-144

PL

System identyfikacji obszaru zagrożenia dla operatora stanowi pierwszy moduł, opracowywanego w Akademii Morskiej w Gdyni, komputerowo wspomaganego systemu projektowania bezpiecznych siłowni okrętowych. W artykule wyróżniono system decyzyjny identyfikacji obszaru zagrożenia, a następnie przedstawiono go za pomocą opisu dążenia do zamierzonego celu, wykorzystując w tym celu formalną interpretację ogólnego problemu podejmowania decyzji. Na podstawie tego opisu sformułowano zadanie identyfikacji oraz wyznaczono i określono charakterystyczne cechy zbiorów elementów systemu decyzyjnego, tj. zmiennych wejściowych, wynikowych oraz elementów obszaru zagrożenia. Przedstawiono także założenia budowy zbioru miar wartości umożliwiającego pomiar stopnia dążenia systemu decyzyjnego do celu oraz zdefiniowano wskaźniki realizacji tego celu.

EN

Many international reports show us that the most dangerous spaces of ships are their power plants. Moreover, their specificity allows us to assert that their every space can be more or less dangerous for operators carrying out any kind operation. For this reason, ship power plants should be well-designed to minimize possible hazards for their operators. Therefore, the International Maritime Organization has paid attention to this factor by developing guidelines including general principles for design of safe ship power plants. As a rule, they do not have an obligatory character and therefore engineers can ignore them. Today, in order to force engineers to take into account the mentioned guidelines, many maritime design offices have introduced so-called quality control systems to the design process like ISO or TQM. According to these systems, engineers responsible for safety issues have to participate in design reviews. In this approach, they can offer some remarks and suggestions concerning design solutions but only after the fact. Acceptance of their suggestions can trigger off the necessity for redesign which, in turn, could entail increasing the design cost and time. The paper deals with the computer-aided system for hazard zone identification in ship power plants. Some issues connected with modelling of a decision-making process coursing in the developed decision-making system are presented. Particularly, for enabling an appropriate course of that process, we have constituted the framework in the form of a decision-making system. In this decision-making system, we selected the following system elements: a set of input variables (dangerous and harmful factors which can trigger off hazards for operators); a set of elementary hazard situations (collection of a ship machinery component and an operational activity constitutes the set of an elementary hazard situation); a set of output variables (types of hazards for operators), a set of decisions and a set of comparative values allowing to compare the decisions to be reached by the user's system. Moreover, we distinguished the following two functions; influence of dangerous and harmful factors on hazards for operators (triggering off potential hazards for operators) and assessment of a hazard level. Any combination of these elements sets up the decision-making system for hazard zone identification in a ship power plant. Nevertheless, the presented functions allow us to consider such a system as relations between its inputs and outputs variables. According to the existing relations between sets of these variables, we can develop various types of desired models. In our approach, we have adopted relations in the form of prepositional functions. When we want to apply these functions, then we have the question: how to evaluate their logical values? In our opinion, assessments of experts in the field of design, operation, and maintenance of ship power plants could be successively used for this purpose. Their experience, intuition, and understanding of the nature of the matter should allow them to assess the influence of dangerous and harmful factors on hazards for operators and the hazard level. Moreover, the developed decision making system of hazard zone identification sets up the space of possible solutions facilitating knowledge acquisition from experts. It is obvious that experts can formulate their opinions using verbal language. In many cases, such opinions are ambiguous and cannot be analyzed by computers. Therefore, these opinions should be converted into language that can be interpreted by computers.