Semi-Automatic Optimization Using Specialized Instructions

Návrh instrukční sady aplikačně specifických procesorů je náročná úloha. Tato práce popisuje problematiku výběru, označení a vytvoření instrukčních rozšíření aplikačně specifických procesorů. Použitá semiautomatická metoda umožňuje uživateli snadný výběr instrukčních rozšíření pomocí označení úseku zdrojového kódu aplikace. Samotné vytvoření nové instrukce v modelovacím jazyku je řešen automaticky. Tím nechá uživatele soustředit se na činnost, při které se nejvíce uplatní vynalézavost a zkušenosti člověka.The design of instruction sets for application specific processors is a difficult task. This thesis describes the tasks of selection, marking and creation of instruction set extensions for application specific processors. The presented semiautomatic method provides the user with a simple way to select instruction set extensions by marking a section of source code in the application. The creation of the new instruction in the modelling language itself is solved automatically. Thanks to this the user can concentrate his efforts on tasks where human ingenuity and experience can be used the most.

Frictional Contact Finite Element Analysis of Pneumatic Cylinders

Friction is present in most mechanical systems. The aim of this paper is to analyse friction between a pneumatic cylinder and its piston seal using the finite element method (FEM). The high-fidelity numerical model used real geometry and material characteristics of a double acting pneumatic cylinder. The simulations required fine tuning: the piston seal was created with a hyperelastic, nearly incompressible material model utilizing mixed u-p elements. Three friction characteristics were analysed with slow velocity motion of the piston: Coulomb, an extended Coulomb and the Benson-Hallquist model. The result of the Coulomb model has given a constant friction force after an oscillation at first. The extended Coulomb friction model is used to show the effect of cohesion between two surfaces. After that, the Benson-Hallquist model was simulated by FE and then experimental and FE results were compared. As a result, an exponentially decreasing friction force was obtained. It was shown that the friction behaviors can be simulated with FE and this method will allow studying the effects of different types of piston seal and cylinder barrel on the friction force

Selection of winter cereals for organic agriculture

Productivity in agriculture has more than tripled in developed countries since the 1950s. Beyond the success of plant breeding, the increased use of inorganic fertilizers, application of pesticides, and spread of irrigation also contributed to this success. However, impressive yield increases started to decline in the 1980s because of the lack of sustainability. One of the most beneficial ways to increase sustainability is organic agriculture. In such systems the prerequisite of successful farming is the availability of crop genotypes that perform well. However, selection of winter cereals for sub-optimal growing conditions is still neglected, and the organic seed market also lacks of information on credibly tested varieties suitable for organic agriculture

Optimised dairy cow feeding economy in Hungary

High yielder cows optimal feeding is always a major question in farm management. We attempted to find the optimal yield- and weight group in a Holstein_Freisian herd. Handled more than 2000 milk record samples and concluded that the optimal body weight is about 600-650 kg. Also step up from medium yielder to high yielder is more cost efficient than pushing the milk production over 30 kg milk daily. Our results show that fitness traits and body scores are major factors and every 50 kg of extra weight rises the forage cost in average of 0,11 €cents. The mid-weight cows produce 25 kg of milk daily but the herds are very heterogeneous. The solution should be smaller cows, homogeneous herds and optimized feeding. Keywords: milk, cost, feeding, Freisian

Simulation of the Working Diameter in 3-Axis Ball-end Milling of Free Form Surface

Free-form surfaces are used in many aspects of the industry. When machining these surfaces using three-axis ball-end milling, the tool\u27s working diameter continuously changes, due to the change in the surface geometry which affects the surface quality. This change in working diameter occurs from one point to another and continues along the surface even in the case of a constant tool path. Using a simultaneous five-axis milling machine can solve the problem, however, this solution comes at a high cost and complexity. This paper gives insight into the calculation of the effective diameter at each point of the milled surface and presents the effect of the different parameters by simulation. The simulation applies the geometric method, based on the coordinate transformation of the intersection curve. The presented simulation approach ensures optimization method for both the cutting process and the tool path. The ultimate goal is to reduce the cutting speed change considering the change of the current working diameter by controlling the spindle speed point to point, resulting in a more homogeneous surface