Modeliranje dinamike zaliha

Ovaj rad je detaljnija obrada članka autora Luce Pieronia i Mattea Ricciarellia pod nazivom: ”Modelling dynamic storage function in commodity markets: Theory and evidence” odnosno prevedeno na hrvatski : “Modeliranje funkcije dinamičkog skladištenja na tržištima roba: Teorija i dokazi”. U radu, slijedeći tzv. modernu teoriju skladištenja, modeliramo cijene robe u međuvremenskom okviru u kojem racionalni subjekt može prenositi robu kao zalihe iz trenutnog u buduće razdoblje zbog špekulativnih potreba i opreza. U prvom poglavlju opisujemo ekonomsku teoriju i motivaciju koja se nalazi iz svjetskog tržišta metala, konkretnije bakra. U drugom poglavlju uvodimo pojam Hamiltonijana te definiramo optimizacijski problem i ograničenja zajedno s postupkom optimizacije funkcije cilja. U trećem poglavlju navodimo potrebne alate za ekonometrijsku analizu dok u četvrtom poglavlju primjenjujemo navedene alate na podacima. U petom poglavlju komentiramo podatke i dobivene rezultate. U šestom poglavlju dajemo zaključak te komentiramo ponašanje ekonomskih agenata s obzirom na Tobinovo q.This paper is more detailed version of the article by authors Luca Pieroni and Matteo Ricciarelli: “Modelling dynamic storage function in commodity markets: Theory and evidence” . In this paper, by following so called modern theory of storage, we model commodity prices in an intertemporal framework, in which, a rational subject can carry commodity as stocks from present to the future period for speculative purposes and caution. In first chapter, we describe economic theory and motivation behind world metal market, particularly copper market. In second chapter, we introduce the Hamiltonian and define optimization problem with it's constraint together with optimization procedure. In third chapter, we mention necessary tools for econometric analysis while in fourth chapter, we apply those tools on our data. In fifth chapter, we comment on data and results. The conclusion is given the in sixth chapter, together with a comment on behaviour of economic agents with the respect to the Tobin's q

Modeliranje dinamike zaliha

Ovaj rad je detaljnija obrada članka autora Luce Pieronia i Mattea Ricciarellia pod nazivom: ”Modelling dynamic storage function in commodity markets: Theory and evidence” odnosno prevedeno na hrvatski : “Modeliranje funkcije dinamičkog skladištenja na tržištima roba: Teorija i dokazi”. U radu, slijedeći tzv. modernu teoriju skladištenja, modeliramo cijene robe u međuvremenskom okviru u kojem racionalni subjekt može prenositi robu kao zalihe iz trenutnog u buduće razdoblje zbog špekulativnih potreba i opreza. U prvom poglavlju opisujemo ekonomsku teoriju i motivaciju koja se nalazi iz svjetskog tržišta metala, konkretnije bakra. U drugom poglavlju uvodimo pojam Hamiltonijana te definiramo optimizacijski problem i ograničenja zajedno s postupkom optimizacije funkcije cilja. U trećem poglavlju navodimo potrebne alate za ekonometrijsku analizu dok u četvrtom poglavlju primjenjujemo navedene alate na podacima. U petom poglavlju komentiramo podatke i dobivene rezultate. U šestom poglavlju dajemo zaključak te komentiramo ponašanje ekonomskih agenata s obzirom na Tobinovo q.This paper is more detailed version of the article by authors Luca Pieroni and Matteo Ricciarelli: “Modelling dynamic storage function in commodity markets: Theory and evidence” . In this paper, by following so called modern theory of storage, we model commodity prices in an intertemporal framework, in which, a rational subject can carry commodity as stocks from present to the future period for speculative purposes and caution. In first chapter, we describe economic theory and motivation behind world metal market, particularly copper market. In second chapter, we introduce the Hamiltonian and define optimization problem with it's constraint together with optimization procedure. In third chapter, we mention necessary tools for econometric analysis while in fourth chapter, we apply those tools on our data. In fifth chapter, we comment on data and results. The conclusion is given the in sixth chapter, together with a comment on behaviour of economic agents with the respect to the Tobin's q

THE YIELD AND LAND RECLAMATION PROBLEMS OF AGRICULTURAL LAND OF ŠEMOVEC AREA

The detailed soil survey, land reclamation and crop production investigations are made for 706 hectars of Šemovec area. Investigated area belongs to the rather flat river Drava alluvial valley. The soils are semigley and hypogley with maximum height of groundwater talble for semigley soils 1—2 meters and for hypogley less than 1 meter. Changes in groundwater levels including water table are caused by changes in groundwater storage of unconfined phreatic aquifer and due to reduced natural water regime of river Drava and water regime of river Plitvica channel. The texture of semigley and hypogley topsoil is mostly silty loam while unconfined aquifer is mixture of gravel and sand (graf. 1). Effective soil depth vary from shallow (20—60 cm) to deep (more than 100 cm). Average content of available soil water is 150 mm/m (graf. 4) while infiltration rate of surface layers is very high. The primary source of water of semigley topsoil is rainfall. In general the rainfall in this humid area vary widely m respect to amount and frequency (graf. 2, 3). The present crop production is mostly extensive due to crop rotation and yields. The present land suitability for intensive crop production is evaluated in respect to suitable (S-1, S-2, S-3) and unsuitable (N-1, N-2) land classes. Limitations for intensive crop production are mostly due to some combinations of fertility status, effective soil depth and unregulated soil water regime. There are two land reclamation units. One priority for agroamelioration of 642 hectars (semigley) and another one of priority for agro and hydroamelioration of 58 hectara (hypogley). Land reclamation must be done in order to some combinations of soil loosening, soil fertilization (450 kg PgOg and KgO), supplementary irrigation (due to maximum monthly deficit of available soil water approximately 78 mm including net hydromodul 0,29—0,311/sec/ha), introduction of new crop rotations and soil drainage

APPARENT SPECIFIC GRAVITY AND SOIL MOISTURE INTERVAL AS FACTORS IN GROWING WINTER WHEAT

The paper presents the results of preliminary investigations into the effects of apparent specific gravity and the soil moisture interval, and also of their combinations, upon the yield of winter wheat and the nitrogen content in the grain. The investigations were carried out on for different soil types in greenhouse model experiments: on red soil, pseudogley, brown soil on carbonate less and alluvial soil. For each soil type three different apparent specific gravities were tested - 1.2,1.4 and 1.6 kg/cu. dm, and there different moisture intervals - 0.33 to 1.00, 0.33 to 6.25 and 0.33 to 15.00 atm, as well as their combinations. Before the experiment was set up, the main physical and chemical properties of the soil were determined (Tables 1, 2 and 3). The results relating to the grain and straw yields and the nitrogen content in wheat grain are presented accoRding to soil types and the investigated factors in Tables 4-8 and in Graphs 1-9. It can be generally stated that the apparent specific gravity of the soil had various effects upon the grain and straw yields of winter wheat and that the medium or highest apparent specific gravity was regularly better than its low value. The effects of the soil moisture interval on the grain and straw yields was less variable, for in almost all cases there was a tendency of highest efficiency at the lowest moisture interval. The combinations of the apparent specific gravity and the soil moisture interval, though showing some interactional effect, did not give enough elements for drawing a firm conclusion about their reciprocal compensation or their optimal effect. The effect of the investigated factors on the nitrogen content in winter wheat grain varies considerably, both as regards their individual and mutual effects. There was no effect of the moisture interval, while the effect of the apparent specific gravity was felt only in an indirect way. Although the investigations were only orientational, they enabled, from the aspect of the investigated factors, to determined the interrelation of the more important physical properties in relation to the grain and straw yield and the accumulation of nitrogen in wheat grain. They also give the guidelines for further investigations, particularly those to be carried out in the field

Surface and Ground Water Regime in Biđ-field Soils

The aim of this work was to determine, through several-years stationary investigations, the water regime of soils in the Biđ-field district. Investigations were carried out during a three-year period (2001-2003) on 8,700 ha of agricultural areas. Detailed hydropedological investigations were done in 2000 and a soil map of the district (scale 1:10,000) was produced. Five pedosystematic units were detected: semigley, pseudogleyed, eugley hypogley, eugley amphigley, humogley, and drained soils. Based on three-year continuing monitoring of surface and ground waters the following main types of moistening of the soils were identifi ed: eugley-pseudogley, hypogley, amphigley and drained. Stochastic relation between the Sava and Biđ water levels and groundwater in the agrological profile of studied soils was determined by crosscorrelation with one decade shift s (c = 1). It was found that the ground waters in the profi les of studied soils communicate more intensively with the River Biđ water (r = 0.65-0.69) compared to the River Sava water (r = 0.23-0.69). This especially applies to ground water of hypogley soils, which cover 57% of the studied area. Marked vertical communication of ground water in the deep aquifer with water of the shallow soil aquifer was detected, indicating that the surface layer, mainly made up of silty clayey loams, is not impervious