Availability is one of the most used terms in maintainability engineering. This concept is used to denote: The quality of service of an engineering system, i.e., machines, weak points' analysis, asset management, as well as making decisions in the process of life cycle management. Availability is an overall indicator and contains partial indicators that are oriented towards reliability, maintenance, and logistical support. Availability presents a variable value and changes in time and space. Usually, availability is shown as the coefficient of time use of the machine. This approach is not good enough because it does not go into the structure of the availability itself and requires a high level of IT support in system monitoring. In this sense, this paper will use the fuzzy theory and the corresponding analytic hierarchy process (AHP) multi-criteria analysis to present a conceptual and mathematical model for the assessment of availability based on expert judgment. The model will be shown in the case study (on the example) of bulldozers working in the open-pit lignite mine.Energies 2019, 12, 4044 2 of 18 defines availability as a measure of the degree to which an item is in an operable state and can be committed at the start of a mission when the mission is called for at an unknown (random) point in time. Availability, as measured by the user, is a function of how often failures occur and corrective maintenance is required, how often preventative maintenance is performed, how quickly indicated failures can be isolated and repaired, how quickly preventive maintenance tasks can be performed, and how long logistics support delays contribute to downtime [4].Achieving a satisfactory level of the machine availability in the use phase depends largely on appropriate maintenance procedures, logistical support, and the provision of appropriate means of maintenance. A variety of activities are involved in the attempt to reduce active and inactive maintenance time. The mentioned times are related to the maintenance work itself, as well as to the appropriate technical, logistical, and administrative waiting times. This requires appropriate efforts in planning and creating a realistic maintenance concept, a critical analysis of maintenance plans (maintenance levels, identification of needs, goals), defining requirements for logistics support tools (people, training, manuals, test, and auxiliary instruments, spare parts, etc.).In the last decades of the 20th century, the concept of dependability management [5,6] was developed by the International Electro-Technical Commission (IEC) in order to provide an integrated approach to managing and ensuring: Safety management, availability, reliability, convenience of maintenance, and maintenance support system. This concept is also designated as an international standard IEC 300 [5], which, among other things, states that the performance of dependability includes availability as its measure [6]. Dependability is defined in [7] as "the ability to avoid service failures that are more freque...

In a continuous system of production in open-cast coal mining, in addition to the basic machinery which consists of highly productive machines (bucket-wheel excavators, bucket-chain excavators, spreaders, conveyor-belt transporters, etc.) that provide an uninterrupted exploitation of mineral ores, the usage of auxiliary machinery is also necessary. The auxiliary machinery provides the possibility of using the capacities of basic machinery adequately and timely. Further, it must be mentioned that the auxiliary machinery generates up to 20% of the total mining expenses. Dozers are the most commonly used machines. Choosing the adequate dozer of the right type and manufacturer is of great importance and can be made easier by carrying out an analysis of the existent operational-exploitative parameters. In this paper, the method of grading the operational-exploitative parameters of dozer is defined. The choice of the optimal type of dozer was conducted by using the analytical hierarchy process (AHP).

Rad sadrži nove podatke o Tomi Živanoviću. Iako je on u Srbiji danas poznat kao naučnik svetskog glasa i žrtva komunističkog režima, o Živanoviću postoji i jedna usmena tradicija, koja ga pamti kao sebičnog, škrtog i svadljivog čoveka, moralno neispravnog i nespremnog da pomogne studentima. Rad kritički ispituje tu tradiciju i delimično je potvrđuje a delimično opovrgava. Živanović je patio od kompleksa inferiornosti, pa je u socijalnoj komunikaciji reagovao arogantno i agresivno. U mladosti je njegova socijalna integracija bila otežana, ali je kasnije ušao u najviše krugove jugoslovenskog društva, delom zahvaljujući supruzi. Njegovi rani radovi o tripartitnom sistemu krivičnog prava i sintetičkoj pravnoj filozofiji bili su dobro primljeni, a on sam je bio istaknut član međunarodnih udruženja za krivične nauke i učesnik svih značajnijih skupova iz te oblasti. Po dolasku komunista na vlast je penzionisan, ali je kao član Akademije nauka vodio istraživačke projekte i putovao u inostranstvo na studijske boravke i međunarodne kongrese. U teorijskom pogledu, u ovom periodu Živanović nije stvorio ništa novo. Naprotiv, postao je opsednut značajem sopstvenih ranijih doprinosa, koje je smatrao univerzalno primenljivim "otkrićima". Ova opsednutost je poljuljala njegov smisao za stvarnost, pa je sebe dva puta kandidovao za Nobelovu nagradu. Ocena Živanovićevog doprinosa pravnoj teoriji koja preovlađuje u domaćoj literaturi je preterana, mada nema sumnje da je između dva svetska rata on spadao među dvadesetak najuglednijih teoretičara prava u svetu.

Elinor Ostrom thinks she has discovered a third way apart from private and government property: the commons. In her view, there is no "tragedy" associated with this third option. The present article takes strong issue with her. Our claim is that she has not properly distinguished between a commons and partnership arrangements. In the former case, outsiders cannot be excluded from entry; in the latter, they can. The reason for this confusion between the commons and private property in Ostrom's work is that she believes private property is possible only if government protects and enforces it. We show by using various historical examples that this assumption is wrong, and hence the central tenet of Ostrom's model of the commons fails.

This book is an inclusive and well-defended libertarian analysis of the political and economic forces at work in America up to the civil-war years."-Svetozar (Steve) Pejovich, Professor Emeritus, Economics, Texas A&M University, USA "Based on solid historical research and representing a quite novel approach, this book is an original contribution to the immense literature on the subject of American political thought at the Founding and beyond." -