Ante Galić

A Modelling and Optimization Framework for Real-World Vehicle Routing Problems

The globalisation of the economy leads to a rapidly growing exchange of goods on our planet. Limited commodities and transportation resources, high planning complexity and the increasing cost pressure through the strong competition between logistics service providers make it essential to use computer-aided systems for the planning of the transports. An important subtask in this context is the operational planning of trucks or other specialized transportation vehicles. These optimization tasks are called Vehicle Routing Problems (VRP). Over 1000 papers about a huge variety of Vehicle Routing Problems indicate the practical and theoretical importance of this NP-hard optimization problem. Therefore, many specific solvers for different Vehicle Routing Problems can be found in the literature. The drawback is that most of these solvers are high specialized and inflexible and it needs a lot of effort to adapt them to modified problems. Additionally, most real world problems are often much more complex than the idealized problems out of literature and they also change over time. To face this issue, we present an integrated modelling and optimization framework for solving complex and practical relevant Vehicle Routing Problems. The modular structure of the framework, a script based modelling language, a library of VRP related algorithms and a graphical user interface give the user both reusable components and high flexibility for rapid prototyping of complex Vehicle Routing Problems.

Variation in the Bioactive Compound Content at Three Ripening Stages of Strawberry Fruit

During the harvest season of two consecutive years, five strawberry cultivars (‘Arosa’, ‘Elsanta’, ‘Marmolada’, ‘Miss’ and ‘Raurica’), grown in the continental part of the Republic of Croatia, were examined. Strawberry fruits quality was evaluated by individual phenol compounds, individual anthocyanins and fruit color. Fruits were harvested in three different periods. Analyzed strawberry cultivars show very good average values of the studied phenolic acids and flavonoids with predominant caffeic acid and epicatechin content in all researched strawberry cultivars. Considering the content of individual anthocyanins, pelargonidin 3-glucoside is predominant in strawberry extract followed by cyanidin-3-glucoside and pelargonidin 3-rutinoside. The correlation between individual anthocyanin content and chromaticity parameters was detected in all strawberry cultivars, additionally correlation coefficients and statistical significance were much lower. The results show a positive association between cultivar and harvest time on strawberry pulp color, with each of the color variables, a, b, a/b ratio, C, L and h° values.

Ultrasound-assisted extraction of bioactive compounds from lemon balm and peppermint leaves

Abstract The aim of this study was to investigate the influence of conventional and ultrasound-assisted extraction (frequency, time, temperature) on the content of bioactive compounds as well as on the antioxidant activity of aqueous extracts from fresh lemon balm and peppermint leaves. Total phenols, flavonoids, non-flavonoids, total chlorophylls, total carotenoids, and radical scavenging capacity were determined. Moreover, the relationship between bioactive compounds and antioxidant capacity was studied by linear regression. A significant increase in all studied bioactive compounds during ultrasonic extraction for 5 to 20 min was found. With the classical extraction method, the highest amounts of total phenols, flavonoids, and antioxidant activity were determined, and the maximum amounts of total chlorophylls and carotenoids were determined during 20 min ultrasonic extraction. The correlation analysis revealed a strong, positive relationship between antioxidant activity and total phenolic compounds.

Empirical analysis of two different metaheuristics for real-world vehicle routing problems

We present two hybrid Metaheuristics, a hybrid Iterated Local Search and a hybrid Simulated Annealing, for solving real-world extensions of the Vehicle Routing Problem with Time Windows. Both hybrid Metaheuristics are based on the same neighborhood generating operators and local search procedures. The initial solutions are obtained by the Coefficient Weighted Distance Time Heuristics with automated parameter tuning. The strategies are compared in an empirical study on four real-world problems. A performance measure is used that also considers multiple restarts of the algorithms.

Antioxidant Potential of Fruit Juice with Added Chokeberry Powder (Aronia melanocarpa)

The purpose of this study was to determine the possibility of using chokeberry powder as a supplement in apple juice to increase the nutritional value of the final product with the aim of developing a new functional food product. Also, to determine the influence of ultrasound assisted extraction on the bioactive compounds content, nutritional composition and antioxidant potential of apple juice with added chokeberry powder. The juice samples with added chokeberry powder had higher antioxidant capacity, irrespective of the extraction technique used. Apple juice samples with added chokeberry powder treated with high intensity ultrasound had significantly higher content of all analyzed bioactive compounds. The application of high intensity ultrasound significantly reduced the extraction time of the plant material. A positive correlation between vitamin C content, total phenols, flavonoids and anthocyanins content and antioxidant capacity was determined in juice samples with added chokeberry powder treated with high intensity ultrasound.

Mechanical properties of ten-egg boxes made of different materials

This study was conducted to evaluate mechanical properties of ten-egg boxes, which are the most commonly used egg boxes in many countries of Central and South-Eastern Europe. Six ten-egg boxes were tested, two made of cardboard, two made of expanded polystyrene and two made of general purpose solid polystyrene, each from a different producer. There were no significant differences in basic dimensions between tested boxes of various materials, while the significant differences were occurred in weight and box wall thickness. Test included measuring of vertical forces required for deforming complete box and at particular place for each egg in a box till contact with eggs. According to the obtained results, cardboard boxes can provide the best mechanical protection for eggs. The average force required for deforming complete cardboard box was 83.6% higher than for solid polystyrene box, and even 289.5% higher than for expanded polystyrene box. The average force required for deforming cardboard box at particular place for each egg in a box was 60.8% higher than for polystyrene box, and 74.0% higher than for expanded polystyrene box. The disadvantage of cardboard boxes is that they are not resistant to the impact of moisture as polystyrene boxes and in the case of an increase in box moisture due to storage in inappropriate conditions their mechanical resistance decreases.

Bioactive compounds, pigment content and antioxidant capacity of selected cabbage cultivars

Abstract The main aim of this research was to determine the amount of bioactive compounds and antioxidants, as well as differences in chemical composition between six cabbage cultivars. Also, the amount of pigment compounds and relationship between chromaticity parameters between selected cabbage cultivars was determined. The significant differences (p≤0.0001) of all analyzed chemical parameters were determined. According to the obtained results of pigment composition, white cabbage cultivars contained the higher amounts of total chlorophylls (average 3.15 mg g-1 fresh weight), while red cabbage cultivars contained the higher amounts of anthocyanins (average 696.08 mg kg-1 fresh weight). Red cabbage cultivars contained the higher amounts of biologically active compounds. Average values of total phenols, total flavonoids, non-flavonoids and vitamin C were as follows: 172.45 mg GAE 100 g-1 fresh weight, 88.88 mg GAE 100 g-1 fresh weight, 83.59 mg GAE 100 g-1 fresh weight and 28.49 mg 100 g-1 fresh weight. Higher antioxidant capacity was determined in red cabbage cultivars. On average, in red cabbage cultivars even 3.9 times higher antioxidant capacity was determined compared to the selected white cabbage cultivars.

Some Physical, Morphological and Mechanical Characteristics of Turkey (Meleagris gallopavo) Eggs

The physical, morphological, and mechanical characteristics of eggs play an important role in the processes of embryo development and hatching. Some physical, morphological, and mechanical characteristics of turkey (Meleagris gallopavo; Zagorje breed) eggs collected during two laying cycles from same turkey hens were determined in this study. The average values of length, width, geometric mean diameter, weight, surface area, volume, sphericity, eggshell thickness, and eggshell density were determined as 66.61 mm, 46.84 mm, 52.66 mm, 77.74 g, 8712.42 mm2, 76553.49 mm3, 79.31%, 0.354 mm and 3.13 g cm-3, respectively. Eggs collected during second laying cycle were, on average, larger and heavier in comparison with those collected during first cycle. Average albumen, yolk and eggshell percentages of the eggs collected during two laying cycles were 58.11%, 29.50% and 12.39%, respectively. The highest breaking strength was obtained when the eggs were loaded along the X-front axis and the least breaking strength was required along the Z-axis. The average breaking strength, absorbed energy and firmness in loading along the X-front axis were found to be 73.80 N, 9.75 N mm and 280.30 N mm-1, respectively.

A nonlinear impact of low energy laser beam on corn kernel drying

This paper describes the investigation of low power laser beam application to corn kernels using kernel moisture as a control parameter. Kernel moisture was measured according to HRN ISO 6540:2002 procedure. Two red laser sources of 100mW and 200mW, λ= 632nm, were used in experiments, both with different exposure time. The power density of laser beam was in range from 0.5mJ/cm2 to 20mJ/cm2. Corn kernels were humidified in seven grades: between 15% and 31% of kernel moisture. All groups of corn kernels were exposed to laser beam for four different exposition times. After laser beam treatment corn kernels moisture was determined by the same HRN ISO 6540:2002 procedure. Obtained results exhibit a high nonlinearity effect giving unexpected increase in moisture for 0.62 % for specific initial moisture and for specific exposition time. Also, the decrease of moisture for 0.5 % was observed for specific lower initial moisture and specific exposure time. The effects are now under further cross-examinations.