Nenad Ristić

Optimizacija zaštite turističkih agencija od kompjuterskog kriminala

Nauka i praksa bezbednosti informacija na Internetu usla je u svoju zreliju fazu. Dostupni su brojne metodologije za procenu rizika (preko 200), standardi zastite, katalozi ranjivosti, pretnji i mera (kontrola) zastite. Metodologija za procenu rizika informacija (ISO/IEC 27005:2008) usvojena je i u finansijskom sektoru u sporazumu BASEL II za procenu operativnog rizika. Iako standardizacija znacajno smanjuje kompleksnost uvođenja sistema zastite, implementacija osnovnih mera zastite za smanjenje rizika na prihvatljiv nivo, jos uvek je složena, skupa i zahteva specificna znanja i iskustva. Problem online krađe licnih podataka i brojeva platnih kartica odnosi se upravo na turisticke agencije gde klijenti masovno placaju racune platnim karticama. U ovom radu autori sugerisu optimalan okvir za upravljanje zastitom informacija u Internet okruženju u turistickim agencijama, sa ciljem da se smanji kompleksnost i da se iste ohrabre da organizovano uvode sistem i praksu zastite informacija, prema svojim potrebama i resursima.

Environmental Aspects of Red Mud and Its Utilization as a Component of Building Materials

The Bayer process is the main industrial process covering 90 % of global production of alumina. The sintering process deals with the medium and low grades of bauxite resource. During the alumina production process, red mud is generated as a waste rock which consists of: hematite, Goethite, quartz, boehmite, calcite, tricalcium aluminate, zinc and magnesium oxides, sodium hydroxide etc. Due to high viscosity of the mud, prior to transport to the waste industrial water is added in the share of 10–15 % prior to transport to the waste disposal dump so that the pipeline transport would be facilitated. What makes red mud a hazardous pollutant is the alkaline liquid phase (Zlaticanin et al. in Prot Mater 53:292–298, 2012, Paramguru et al. Extr Metall Rev 26:1–29, 2005) [1, 2]. From the aspect of stored quantities, red mud represents a significant environmental problem (Zlaticanin et al. in Prot Mater 53:292–298, 2012) [1]. A large number of methods for sustainable disposal of red mud was developed, however, it a tendency to use the red mud in other production process, up to 20 % of it until 2025. The potential for utilization of red mud is seen making masonry products, ceramic tiles, in replacement of a part of cement or aggregate, as a component in self-compacting concretes, geopolymers. The paper provides a review of the developed methods for storage of red mud, with a goal of sustainability and cost-effectiveness. Simultaneously, the paper provides the review of potential application of red mud as a component of building materials. In the experimental part was considered the usage of red mud as a mineral admixture for making self-compacting concrete.

The Improvement of the Inventory Process in the Company "Benlian Food" Niš by Applying the Pom-Qm 4.0 Software

One of the most important factors of an enterprise’s efficiency is also adjusting of supply with demand requirements. Logistics, as an integral function of an enterprise that establishes and develops relations with the environment and, in a targeted manner, directs the subsystems of a company towards the main goal of its existence and operation, is the most appropriate tool for managing an enterprise in the modern dynamic environment. In many enterprises, inventory optimization is a major problem. Mainly, such enterprises are characterized by poor customer service, such as failure to adhere to delivery deadlines. Bearing in mind the state of Serbian companies, few enterprises can boast their applied scientific knowledge in the field of inventory optimization in practice. The subject of our research is the optimization of the inventory in the company Benlian Food Niš. The management of the company finds it rather significant to know approximately exact quantities needed for the next year. Given the fact that this is an importing company with its production, too, more precise quantities would be of great help, as this would enable management to make more adequate decisions on when and how many products to import and produce.

HYDRO-ABRASIVE RESISTANCE AND MECHANICAL PROPERTIES OF CONCRETE WITH ADDED FLY ASH

The durability of hydraulic engineering structures mostly depends on the resistance of their concrete surfaces to mechanical abrasion. In this paper, we study the hydro-abrasive resistance and mechanical properties of concrete in which cement is partially replaced with fly ash in various proportions. To evaluate these concretes, we measured their compressive strength, flexural strength, static modulus of elasticity, ultrasound velocity through concrete, and sclerometer rebound. The hydro-abrasive resistance of concrete with 15% fly ash was similar to that of reference concrete without fly ash. However, concretes with more than 15% fly ash exhibited lower resistance to abrasive erosion than the reference concrete. Also, the mechanical properties of the concrete deteriorated as the fly ash content increased.