Queueing System with Potential for Recruiting Secondary Servers

In this paper, we consider a single server queueing system in which the arrivals occur according to a Markovian arrival process (MAP). The served customers may be recruited (or opted from those customers’ point of view) to act as secondary servers to provide services to the waiting customers. Such customers who are recruited to be servers are referred to as secondary servers. The service times of the main as well as that of the secondary servers are assumed to be exponentially distributed possibly with different parameters. Assuming that at most there can only be one secondary server at any given time and that the secondary server will leave after serving its assigned group of customers, the model is studied as a QBD-type queue. However, one can also study this model as a G I/M/1-type queue. The model is analyzed in steady state, and a few illustrative numerical examples are presented

Pseudo steady-state period in non-stationary infinite-server queue with state dependent arrival intensity

An infinite-server queueing model with state-dependent arrival process and exponential distribution of service time is analyzed. It is assumed that the difference between the value of the arrival rate and total service rate becomes positive starting from a certain value of the number of customers in the system. In this paper, time until reaching this value by the number of customers in the system is called the pseudo steady-state period (PSSP). Distribution of duration of PSSP, its raw moments and its simple approximation under a certain scaling of the number of customers in the system are analyzed. Novelty of the considered problem consists of an arbitrary dependence of the rate of customer arrival on the current number of customers in the system and analysis of time until reaching from below a certain level by the number of customers in the system. The relevant existing papers focus on the analysis of time interval since exceeding a certain level until the number of customers goes down to this level (congestion period). Our main contribution consists of the derivation of a simple approximation of the considered time distribution by the exponential distribution. Numerical examples are presented, which confirm good quality of the proposed approximation

STABILITY, INNOVATIONS AND COMPETITIVENESS OF ENTREPRENEURSHIP ORGANIZATIONS AS NATIONAL ECONOMY STRATEGIC RESOURCE AND INTERNAL MODERNISATION SOURCE

Russian economy modernization problems are to be solved on the basis of innovations and very soon, since it is vital for the increase of competitiveness of national economy and economy of domestic enterprises. Discussed in the article are issues related to modern development of business as well as most actual directions of development connected with innovations and integration processes. Reasons of unpreparedness of Russian entrepreneurship for innovative development are revealed. Governmental measures and directions of innovative development are critically analyzed, examples from foreign experience are provided for. Directions of development and increase of competitiveness of enterprises on the basis of innovations and integration are proposed

Modern trends and challenges of development of global aluminum industry

This article overviews complex study into modern trends and challenges of development of global aluminum industry. Dynamics, structure, and segmentation of global aluminum market are discussed in terms of systematic analysis. On this basis strategic map of the industry has been plotted and five forces of competition on global aluminum market have been determined which will influence directly on functioning and development of aluminum producing companies

Discharge characteristics of combined low energy ion source – magnetron sputtering system

The discharge characteristics of a new combined low energy magnetron-ion-source sputtering system are presented. The ignition curves, current-voltage characteristics of the system in dependence on gas pressure, magnitude and topology of magnetic field have been researched both for autonomous operation of the planar magnetron discharge and Hall type ion source in plasma mode and for their combination. Spatial distributions of ion current are also presented.Проведено дослідження розрядних характеристик нової комбінованої низькоенергетичної іоннопроменевої магнетронної розпорошувальної системи з питомими параметрами, які відповідають промисловому виробництву. Досліджено криві запалювання, розрядні характеристики в залежності від тиску робочого газу, величини та топології магнітного поля як при автономній, так і при сумісній роботі планарного магнетронного розряду та джерела іонів холлівського типу у плазмовому режимі. Досліджені просторові розподіли потоків іонів.Проведены исследования разрядных характеристик новой комбинированной низкоэнергетичной ионнолучевой магнетронной распылительной системы с удельными параметрами, отвечающими требованиям промышленного производства. Исследованы кривые зажигания, разрядные характеристики в зависимости от давления рабочего газа, величины и топологии магнитного поля как при автономной, так и при совместной работе планарного магнетронного разряда и источника ионов холловского типа в плазменном режиме. Исследованы пространственные характеристики потоков ионов

Vertically integrated holdings in the system of developing the national complex of iron and steel industry of Russia

This article shows brief results of analyzing the competitiveness of Russian vertically integrated holdings and independent enterprises of the iron and steel industry. Besides, it indicates key areas of this industry development in the external and internal market aspect. The promotion of Russian iron and steel products on the external market can be successful only if the production of enterprises is refocused from creating products of low technological conversions to creating products of high technological conversions

Optical and mass spectra from reactive plasma at magnetron deposition of tantalum oxynitride

Processes in reactive plasma during the magnetron deposition of tantalum oxynitride with ICP activation of reactive gas are studied in dependence on Oxygen fraction. Results of spectroscopic study of optical emission from the plasma and of mass-spectrometry of gas composition in the vacuum chamber in response to ignition of magnetron discharge and inductively coupled plasma are presented. It is shown that dissociation level of all species grows with the magnetron current increase while its dependence on oxygen/nitrogen ratio is non-monotonic.Вивчаються процеси в реактивній плазмі під час магнетронного осадження оксинітриду танталу з ICP-активацією реактивного газу залежно від частки кисню. Представлені результати спектроскопічного дослідження оптичного випромінювання з плазми та мас-спектрометрії газового складу у вакуумній камері у відповідь на запалювання магнетронного розряду та індуктивно зв'язаної плазми. Показано, що рівень дисоціації всіх молекул зростає із збільшенням струму магнетрона, тоді як його залежність від співвідношення кисень/азот є немонотонною.Изучены процессы в реактивной плазме при магнетронном осаждении оксинитрида тантала с ICP-активацией реактивного газа в зависимости от процентного содержания кислорода. Приведены результаты спектроскопических исследований оптического излучения плазмы и масс-спектрометрии состава газа в вакуумной камере при зажигании магнетронного разряда и индуктивно связанной плазмы. Показано, что уровень диссоциации всех молекул растет с увеличением тока магнетрона, а его зависимость от соотношения кислород/азот немонотонна

Innovative Environment Forming as the Most Important Condition of Implementation of Efficient Innovations in the Industrial Entrepreneurship Sphere

The article presents the notion of the innovative environment, considers its components and forming principles, studies the main approaches to forming of the economic system innovative environment

Managing iron and steel enterprises: study of innovative methods of industrial engineering (logistics approach)

Specifics of the logistics approach in managing an iron and steel enterprise is reviewed. Attention is focused on the logistics management issues; the areas of their solution are defined. The article proposes an economic mechanism for managing the logistics activities of iron and steel enterprises, including a set of consistent, mutually agreed management activities and measures that encompasses the cycle of assessing, analyzing and optimizing logistics activities and aims at achieving the performance goals. The mechanism is based on a system of methods, models and techniques and provides for the adjustment and control of deviations, thereby ensuring timely response to the deteriorating parameters of managing the logistics activities of an iron and steel enterprise

Investigation of interaction between ion-beam plasma and processed surface during the synthesis of tantalum diboride and pentaoxide

The paper is devoted to investigation of spatial distributions of ion current density to a sample in technological set-up with magnetron sputtering system and ICP source. The dependence of the ion flux towards the processed surface on the parameters of the deposition process was measured. The following parameters were varied: magnetron discharge power, gas type and pressure, target-sample distance, inductive discharge power, and bias potential applied to the samples. The effect of nonequilibrium heating of the sample surface due to relaxation of kinetic energy of ions, atoms and electrons, as well as energy of exothermic chemical reactions at synthesis of Ta₂O₅ and TaB₂ films is discussed. The influence of sample shape on the ion bombardment is also investigated.Досліджено просторові розподіли щільності іонного струму на зразок у технологічній установці з магнетроном та індукційним джерелом плазми. Виміряно залежності потоку іонів на оброблювану поверхню від параметрів процесу осадження, таких як: потужність магнетрона і індуктивного розряду, тип і тиск газу, потужність, потенціал зсуву на зразок. Обговорюється вплив нерівноважного нагріву поверхні зразка за рахунок релаксації кінетичної енергії іонів, атомів і електронів, а також енергії екзотермічних хімічних реакцій при синтезі плівок Ta₂O₅ і TaB₂. Досліджено вплив форми зразка на іонне бомбардування.Исследованы пространственные распределения плотности ионного тока на образец в технологической установке с магнетроном и индукционным источником плазмы. Измерены зависимости потока ионов на обрабатываемую поверхность от параметров процесса осаждения, таких как: мощность разряда магнетрона и индуктивного разряда, тип и давление газа, мощность, потенциал смещения, подаваемый на образец. Обсуждаются влияние неравновесного нагрева поверхности образца за счет релаксации кинетической энергии ионов, атомов и электронов, а также энергии экзотермических химических реакций при синтезе пленок Ta₂O₅ и TaB₂. Исследовано влияние формы образца на ионную бомбардировку