492 research outputs found

    Performance analysis of manufacturing networks : surplus-based control

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    In the modern market, keeping high competition in brands and varieties in type of products is the way for survival of manufacturing industries. Therefore production control methods with capabilities of quick responses to rapid changes in the demand and efficient distribution of the raw material throughout the network are of importance among leading manufacturers. Nowadays, the production control problem has been widely studied and a lot of valuable approaches including queuing theory, Petri nets, dynamic programming, linear programming, hybrid systems were proposed and some of them are implemented. Though up to this moment many methods have been developed, the factory performance remains a challenging problem for further research. Motivated by this problem we study the performance of several manufacturing networks operated by surplus-based control. In the surplus-based control, decisions are made based on the demand tracking error, which is the difference between the cumulative demand and the cumulative output of the network. The studied networks are a single machine, a manufacturing line, a multi-product manufacturing line, a re-entrant machine and a re-entrant line. The performance analysis is based on the performance factors such as demand tracking errors and inventory levels. Specifically, given the presence of unknown but bounded production speed perturbations as well as demand rate fluctuations, we investigate how close the cumulative production output of a manufacturing network follows its cumulative production demand under a surplus-based control policy. The research is subdivided into theoretical analysis, simulation-based analysis and experimental analysis parts. Theoretical analysis By means of analytical tools, the relation between the production demand tracking accuracy and the inventory levels of the networks is investigated. In order to find this relation, classical tools from control theory are used. Models of production flow processes are formulated by means of difference as well as differential equations. In order to analyze their performance, optimal control theory and Lyapunov theory approaches are exploited. Simulation based analysis By means of simulation tools, the theoretical results on performance are evaluated by time-based simulation models. Thus, all theoretical results are illustrated and confirmed by computer simulation. Also two comparative studies are conducted. The first comparative study is realized in order to test the theoretical results on more accurate models, which are event-based. The results are shown to be in agreement with the theory. The second comparative study is on time-based models, where the behavior of a line, a single re-entrant machine and a re-entrant line is tested under three commonly used surplus-based production policies. The performance of each network is evaluated and the results are presented. Experimental analysis An experimental prototype is invented, designed and developed for education and research purposes. The prototype is a hardware tool that serves as a liquid-based emulator of manufacturing network processes. In its core, the liquid-based emulator consists of several electrical pumps and liquid reservoirs. The electrical pumps emulate manufacturing machine behavior, while the liquid reservoirs serve as the intermediate product storages, also called buffers. In the platform, pumps and tanks can be interconnected in a flexible manner. In that way the prototype permits an easy and intuitive way of studying manufacturing control techniques and performance of several network topologies. A detailed system description is provided. Several network configurations and experimentations are presented and discussed

    Distributivity breaking and macroscopic quantum games

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    Examples of games between two partners with mixed strategies, calculated by the use of the probability amplitude as some vector in Hilbert space are given. The games are macroscopic, no microscopic quantum agent is supposed. The reason for the use of the quantum formalism is in breaking of the distributivity property for the lattice of yes-no questions arising due to the special rules of games. The rules of the games suppose two parts: the preparation and measurement. In the first part due to use of the quantum logical orthocomplemented non-distributive lattice the partners freely choose the wave functions as descriptions of their strategies. The second part consists of classical games described by Boolean sublattices of the initial non-Boolean lattice with same strategies which were chosen in the first part. Examples of games for spin one half are given. New Nash equilibria are found for some cases. Heisenberg uncertainty relations without the Planck constant are written for the "spin one half game"

    СОВЕРШЕНСТВОВАНИЕ АЛГОРИТМА РАСЧЕТА СЛОЖНЫХ НЕЭКВИПОТЕНЦИАЛЬНЫХ ЗАЗЕМЛЯЮЩИХ УСТРОЙСТВ ЭЛЕКТРОУСТАНОВОК С УЧЕТОМ ПРОВОДИМОСТИ ЕСТЕСТВЕННЫХ ЗАЗЕМЛИТЕЛЕЙ

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    Purpose. The method of natural concentrated groundings substitution by the set of electrodes taking them into account in the algorithm of electric characteristics calculation for complicated grounding connections of electric installation is offered. An equivalent model as a set of linear electrodes is chosen in accordance with two criteria: leakage resistance and potentials on the ground surface. Methodology. We have applied induced potential method and methods for computing branched electrical circuits with distributed parameters. Results. We have obtained the algorithm for calculating complex non-equipotential grounding connections, which makes it possible to obtain refined values of the potential distribution in the electric stations and substations with outdoor switchgear. Originality. For the first time, we have taking into account the conductivity of natural concentrated grounds by a set of vertical and horizontal electrodes based on equivalent electrical characteristics applied to a two-layer ground. Practical value. The using of the proposed calculation algorithm in the electric grids of JSC «Kharkivoblenergo» made it possible to determine the values of the potential distribution at short circuit in electrical substation taking into account the influence of the conductivity of natural concentrated groundings.Цель. Целью статьи является разработка алгоритма расчета электрических характеристик неэквипотенциальных заземляющих устройств электроустановок с учетом большого числа естественных сосредоточенных заземлителей, а также собственных активных и реактивных сопротивлений горизонтальных заземлителей. Методика. Проведены теоретические исследования с использованием метода наведенных потенциалов, методов конечных разностей для расчета электрического поля простых заземлителей в земле с двухслойной структурой и последовательного применения метода наведенных потенциалов и методов расчета разветвленных электрических цепей с распределенными параметрами. Результаты. Получен алгоритм расчета сложных неэквипотенциальных заземляющих устройств, позволяющий получить уточненные значения распределения потенциала на территории электроустановки. Научная новизна. Новые положения, по сравнению с известными решениями, состоят в учете проводимости естественных сосредоточенных заземлителей совокупностью вертикальных и горизонтальных электродов, обоснованной по равнозначным электрическим характеристикам применительно к двухслойной модели электрической структуры земли. Практическое значение. Использование предложенного алгоритма расчёта в электрических сетях АК «Харьковоблэнерго» позволили определить значения распределения потенциалов при КЗ на электрической подстанции с учетом влияния проводимости естественных сосредоточенных заземлителей. Скорректированные таким образом результаты расчета дадут более точную информацию о величинах нормируемых параметров по заземляющим устройствам действующих электроустановок. С помощью предложенного алгоритма могут быть получены уточненные значения падения напряжений по заземляющим устройствам при КЗ, а, следовательно, рассчитаны напряжения, воздействующие на изоляцию кабелей вторичных цепей, – параметры, нормируемые по условиям электромагнитной совместимости

    The Synthesis of Agent Produced by Interaction of the Complex Trans-Dichlorodiamminplatinum(II) with Arabinogalactan and its Properties

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    При взаимодействии комплекса транс-дихлородиамминплатины(II) с арабиногалактаном получен новый препарат, который охарактеризован методами РФА, ИК-спектроскопии, УФ- спектрофотометрии и термогравиметрии. Изучены состав и строение этого препарата. Показано, что транс-дихлородиамминплатины(II) удерживаются арабиногалактаном водородными связями, образованными эфирными группами, –С – О – С – NH3-группами исходного комплекса. Получен препарат с новыми фармакологическими свойствами – повышенной растворимостью, пониженной токсичностью и большей эффективностью по сравнению с цис-дихлородиамминплатиной(II)The obtained new product of reaction of the complex trans-dichlorodiaminplatinum(II) with arabinogalactan was characterized by XRD, IR-spectroscopy, UF-spetrophotometry and thermogravimetry. The composition and structure of this product was studied. It has been shown that trans-dichlorodiaminplatinum(II) associated with arabinogalactan through –C-O-C- amino hydrogen of the original complex. The synthesized product has the improved pharmacological properties being more soluble, less toxic and shows a greater anticancer activity as compared to cis-dichlorodiaminplatinum(II

    The effect of different baryons impurities

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    We demonstrate the different effect of different baryons impurities on the static properties of nuclei within the framework of the relativistic mean-field model. Systematic calculations show that Λc+\Lambda_c^+ and Λb\Lambda_b has the same attracting role as Λ\Lambda hyperon does in lighter hypernuclei. Ξ\Xi^- and Ξc0\Xi_c^0 hyperon has the attracting role only for the protons distribution, and has a repulsive role for the neutrons distribution. On the contrary, Ξ0\Xi^0 and Ξc+\Xi^+_c hyperon attracts surrounding neutrons and reveals a repulsive force to the protons. We find that the different effect of different baryons impurities on the nuclear core is due to the different third component of their isospin.Comment: 9 page

    Superrigid subgroups and syndetic hulls in solvable Lie groups

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    This is an expository paper. It is not difficult to see that every group homomorphism from the additive group Z of integers to the additive group R of real numbers extends to a homomorphism from R to R. We discuss other examples of discrete subgroups D of connected Lie groups G, such that the homomorphisms defined on D can ("virtually") be extended to homomorphisms defined on all of G. For the case where G is solvable, we give a simple proof that D has this property if it is Zariski dense. The key ingredient is a result on the existence of syndetic hulls.Comment: 17 pages. This is the final version that will appear in the volume "Rigidity in Dynamics and Geometry," edited by M. Burger and A. Iozzi (Springer, 2002

    The effects of the small t properties of hadronic scattering amplitude on the determination its real part

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    Taking into account the different forms of the Coulomb-hadron interference phase and the possible spin-flip contribution the new analysis of the experimental data of the proton-antiproton elastic scattering at 3.8<pL<6.0 3.8 < p_L <6.0 \ GeV/c and small momentum transfer is carried out. It is shown that the size of the spin-flip amplitude can be determined from the form of the differential cross sections at small tt, and the deviation of ρ(s,t)\rho(s,t) obtained from the examined experimental data of the ppˉp\bar{p} scattering from the analysis \cite{Kroll}, based on the dispersion relations, is conserved in all xamined assumptions. The analysis of the proton-proton elastic scattering at 9<pL<70 9 < p_L < 70 \ GeV/c also shows the impact of the examined effects on the form of the differential cross sections.Comment: 13 pages, 3 figure

    Probability amplitude in quantum like games

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    Examples of games between two partners with mixed strategies, calculated by the use of the probability amplitude are given. The first game is described by the quantum formalism of spin one half system for which two noncommuting observables are measured. The second game corresponds to the spin one case. Quantum logical orthocomplemented nondistributive lattices for these two games are presented. Interference terms for the probability amplitudes are analyzed by using so called contextual approach to probability (in the von Mises frequency approach). We underline that our games are not based on using of some microscopic systems. The whole scenario is macroscopic.Comment: Quantum-like model

    Hypernuclei as chiral solitons

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    The identification of flavored multiskyrmions with the ground states of known hypernuclei is successful for several of them, e.g. for isodoublet H(Lambda) - He(Lambda), A=4, isoscalars He(Lambda) (A=5) and Li(Lambda) (A=7). In other cases agreement is not so good, but the behaviour of the binding energy with increasing baryon number is in qualitative agreement with data. Charmed or beauty hypernuclei within this approach are predicted to be bound stronger than strange hypernuclei. This conclusion is stable against variation of poorly known heavy flavor decay constants.Comment: 9 pages, 1 Fig. Presented at the International Workshops on Nuclear and Particle Physics at 50-Gev PS, NP01 (KEK, Japan, December 2001) and NP02 (Kyoto, Japan, September 2002). Some additions and corrections of numerical results are mad

    Bilateral vestibulopathy and age:experimental considerations for testing dynamic visual acuity on a treadmill

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    Introduction: Bilateral vestibulopathy (BVP) can affect visual acuity in dynamic conditions, like walking. This can be assessed by testing Dynamic Visual Acuity (DVA) on a treadmill at different walking speeds. Apart from BVP, age itself might influence DVA and the ability to complete the test. The objective of this study was to investigate whether DVA tested while walking, and the drop-out rate (the inability to complete all walking speeds of the test) are significantly influenced by age in BVP-patients and healthy subjects. Methods: Forty-four BVP-patients (20 male, mean age 59 years) and 63 healthy subjects (27 male, mean age 46 years) performed the DVA test on a treadmill at 0 (static condition), 2, 4 and 6 km/h (dynamic conditions). The dynamic visual acuity loss was calculated as the difference between visual acuity in the static condition and visual acuity in each walking condition. The dependency of the drop-out rate and dynamic visual acuity loss on BVP and age was investigated at all walking speeds, as well as the dependency of dynamic visual acuity loss on speed. Results: Age and BVP significantly increased the drop-out rate (p ≤ 0.038). A significantly higher dynamic visual acuity loss was found at all speeds in BVP-patients compared to healthy subjects (p < 0.001). Age showed no effect on dynamic visual acuity loss in both groups. In BVP-patients, increasing walking speeds resulted in higher dynamic visual acuity loss (p ≤ 0.036). Conclusion DVA tested while walking on a treadmill, is one of the few “close to reality” functional outcome measures of vestibular function in the vertical plane. It is able to demonstrate significant loss of DVA in bilateral vestibulopathy patients. However, since bilateral vestibulopathy and age significantly increase the drop-out rate at faster walking speeds, it is recommended to use age-matched controls. Furthermore, it could be considered to use an individual “preferred” walking speed and to limit maximum walking speed in older subjects when testing DVA on a treadmill
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