Ivica Veza

Integrating process and ontology to support supply chain modelling

Many researchers have recognised a lack of common framework to support supply chain modelling and analysis and proposed their solutions accordingly. Majority of the approaches proposed are more concerned with building an object model of a supply chain than identifying processes that realistically describe a supply chain. Although object models provide means or building blocks necessary to model and analyse different elements of a supply chain, absence of supply chain processes promotes a ‘black box’ view on the supply chain. This study proposes an ontology model specifically developed to support supply chain process modelling and analysis. It is based on a premise that prior identification of processes the ontology is supposed to support facilitates the ontology development and validation. This study introduces development, validation and application of supply chain ontology to support supply chain process modelling and analysis.

Investigation and modelling of process parameters and workpiece dimensions influence on material removal rate in CWEDT process

Cylindrical wire electrical discharge turning (CWEDT) is a special form of wire electrical discharge machining (WEDM) process, which uses submerged rotation spindle as a clamping device for workpiece rotation in order to produce cylindrical parts. This study aims at determining influence on material removal rate (MRR) of CWEDT as an objective function. In the preliminary experiments, the widely used X5CrNi18–10 (DIN) and hard machinable S390PM (DIN) were used. The results of preliminary experiments showed that the type of steel is not the factor that has a significant influence on MRR. Pulse maximum current, pulse pause time, rotation speed, length of discharge area and cutting radius were used in MRR mathematical modelling by neural network programming. The results of the study exhibit that among the machining parameters, the pulse maximum current has the strongest influence on MRR. When the pulse maximum current increases, MRR increases as well. The discharge area length has an influence on MRR only on higher pulse maximum current values, and by the increase of the discharge area length, the MRR also increases. The derived mathematical model for MRR, which was finally validated and tested, enables calculation of complex cylindrical part production machining time for the given experimental set-up condition.

Solving partner selection problem in cyber-physical production networks using the HUMANT algorithm

The idea of non-hierarchical production networks consisting of autonomous enterprises has been present in scientific community for more than 20 years. Although some global corporations are using their own production networks across continents, they are not similar to the original idea of non-hierarchical production networks in many aspects. It seems that this idea waited for production systems to acquire proper information and communications technology (ICT) or new industrial platforms, like Industry 4.0. The result is a new type of production network called Cyber-Physical Production Network (CPPN). The CPPN is, from ICT point of view, ready to act as non-hierarchical production networks consisting of autonomous production systems with many automated processes. One of the most important processes of the CPPN is a selection of optimal partners (enterprises) to be part of a new virtual enterprise, created inside production network. An optimisation problem emerges in this process, and it is called Partner Selection Problem (PSP). It is non-polynomial-hard combinatorial problem. Since metaheuristic algorithms are well-proven in solving that kind of problem, a specially designed metaheuristic algorithm derived from ant colony optimisation and named the HUMANT (HUManoid ANT) algorithm is used in this paper. It is multi-objective optimisation algorithm that successfully solves different instances of PSP with two, three, four or more objectives.

Selection of the Basic Lean Tools for development of Croatian Model of Innovative Smart Enterprise

The research within project Innovative Smart Enterprise (INSENT) was conducted in order to improve scientific understanding of the current state of Croatian manufacturing industry by promoting empirical, enterprise-level research on technological and non-technological processes and organizational innovation. The aim was to understand how manufacturing enterprise in Croatia acquire new manufacturing technologies, ICT integration within processes, new organizational concepts in production such as group work or relocation of production, new products that emerge from process and organizational innovation such as production-related services, and other demands related to Industry 4.0. In order to develop Croatian model of Innovative Smart Enterprise (HR-ISE model), analysis of global and local enterprises, based on literature review and questionnaires, has been made. A selection of six basic Lean tools is made, and foundations of generic configuration of HR-ISE model are defined. In further research, interviews with CEOs of leading Croatian manufacturing enterprises should help creating completely defined HR-ISE model.

Application of De Novo Programming Approach for Optimizing the Business Process

The linear programming model is sometimes difficult to apply in real business situations due to its assumption of proportionality. This paper shows an example of how to use De Novo programming approach instead of linear programming. In the De Novo programming, resources are not fixed like in linear programming but resource quantities depend only on available budget. Budget is a new, important element of the De Novo approach. Two different production situations are presented: increasing costs and quantity discounts of raw materials. The focus of this paper is on advantages of the De Novo approach in the optimization of production plan for production company which produces souvenirs made from famous stone from the island of Brac, one of the greatest islands from Croatia.

Concept of Information-Technology Cluster in Economy of Split-Dalmatian County

Information-technology cluster is integration of the small and medium IT enterprises (from the Split-Dalmatian county) to business network. Idea is to unify all available resources in the county to achieve competitive IT cluster on national and international level.