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61.
The problem of the determination of preventive control in a steady state, intended to provide the secure operation of a power system, is considered in this paper. The problem is solved using the concept of multicriteria optimization, by minimizing the system generation cost, modified with penalty functions originating in inequality constraints due to operating limits. The penalty functions represent a security index, the value of which depends on the particular outage.A method for a preventive security control is derived, a new numerical procedure for the solution of the problem based on the ?-coupling method applied to steady state problems is presented, and some results of a study of the application of the proposed method on a 31-bus, 40-branch real power system are given. 相似文献
62.
Angelina Ilić Stepić Zoran Ognjanović 《International Journal of Parallel, Emergent and Distributed Systems》2018,33(3):257-275
AbstractIn this paper, we focus on the main results which we have developed to obtain different propositional logics for reasoning about p-adic valued probabilities. Each of these logics is a sound, complete, and decidable extension of classical propositional logic. Also, we show some applications of these logics in modelling cognitions. 相似文献
63.
The effect of heat treatment on microstructure, hardness, tensile properties, fracture mode and wear behaviour during lubricated
and dry sliding of the zinc-based alloy with 25 wt.%Al was studied. Microstructural investigation and chemical analysis of
as-cast and heat-treated specimens, the fracture and worn surfaces, as well as wear debris were performed by scanning electron
microscopy and energy dispersive spectroscopy. Wear tests were carried out using a disc-on block-type wear machine. By a relatively
simple heat treating consisting of a short-term annealing in the single-phase region followed by water-quenching, the elongation
has been markedly improved, while the strength was maintained high. The results indicate that the wear rate strongly depends
on the microstructure, applied load and sliding conditions. The wear rate increases with load, and under dry sliding conditions
the wear rate is approximately two orders of a magnitude higher than under lubricated conditions. During dry sliding the best
wear behaviour was displayed by the water-quenched specimens, whereas slowly cooled specimens showed the higher wear rate.
Lubrication strongly affects the wear behaviour. Contrary to dry sliding, slowly cooled specimens exhibit the best wear properties
under lubricated conditions. The wear mechanisms were proposed for dry and lubricated sliding.
An erratum to this article can be found at 相似文献
64.
An automatic system is described for measuring two-dimensional acoustic velocity fields in solid samples. The measurement is performed by a computer-controlled, mechanically scanned transducer in a liquid bath, and is based on measuring the phase delay of the acoustic wave by a two-pulse echo method. Applications include measuring stress fields due both to externally applied and residual stresses, and microstructure studies of solid samples. 相似文献
65.
Wireless Networks - Applying amplify-and-forward (AF) protocol to orthogonal frequency division multiple-access (OFDMA) relay networks opens questions regarding subcarrier matching and resource... 相似文献
66.
67.
Tomato (Solanum Lycopersicum L.) Processing Main Product (Juice) and By‐Product (Pomace) Bioactivity Potential Measured as Antioxidant Activity and Angiotensin‐Converting Enzyme Inhibition 下载免费PDF全文
68.
Suzana M. Cakić Ivan S. Ristić Milena M-Cincović Nada Č. Nikolić Olivera Z. Ilić Dragan T. Stojiljković Jaroslava K. B-Simendić 《Progress in Organic Coatings》2012
Soft drinks poly(ethylene terephthalate) (PET) bottles were depolymerized by glycolysis with different molar ratio of glycol, such as propylene glycol (PG), triethylene glycol (TEG) and poly(ethylene glycol) (PEG 400), in the presence of a zinc acetate catalyst. These glycolyzed products were characterized by hydroxyl value (HV) determinations. The obtained glycolyzed products were reacted with isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA), as potential ionic center for water dispersibility, and mixed with ethylene diamine (EDA) as extender chain to prepare polyurethane dispersions. The PET glycolyzed products and polyurethane formation were characterized using Fourier transform infrared spectroscopy (FTIR). The molecular masses distribution of oligoester polyol and polyurethane dispersions were determined by using gel permeation chromatography (GPC). The effect of different PET/glycol molar ratio, on the physico-mechanical properties, such as hardness, adhesion test and gloss of polyurethane films were investigated. Thermal properties were investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). 相似文献
69.
In this paper we present a computationally efficient, suboptimal integer bit allocation algorithm that maximizes the overall
data rate in multiuser orthogonal frequency division multiplexing (OFDM) systems implemented in wireless networks. Assuming
the complete knowledge of a channel and allowing a subchannel to be simultaneously shared by multiple users we have solved
this data rate maximization problem in two steps. The first step provides subchannel assignment to users considering the users’
requests on quality of service (QoS) expressed as the minimum signal-to-noise ratio (SNR) on each subchannel. The second step
provides transmit power and bit allocation to subchannels in order to maximize the overall data rate. To reduce computational
complexity of the problem we propose a simple method which assigns subchannels to users and distributes power and bits among
them. We have analyzed the performance of our proposed algorithm by simulation in a multiuser frequency selective fading environment
for various signal-to-noise ratios and various numbers of users in the system. We have concluded that our algorithm, unlike
other similar algorithms, is suitable for OFDM wireless networks, especially when signal-to-noise ratio in the channel is
low. Also, the results have shown that the total data rate grows with the number of users in the system. 相似文献
70.
In this paper we examine some of the general principles and analysis methods that are used to design an automated material handling system. The paper focuses on one type of automated handling system that seems especially suitable for automation in discrete-product manufacturing. These types of automated handling systems are called automated guided vehicle systems. These systems are most applicable for the automation of low-and medium-volume handling situations, where the routeing of materials is more individualised. For guided vehicles, a new quantitative method for analysing these systems is developed in the paper. Examples are presented to demonstrate the method. 相似文献