Journal articles: 'Operating models'

1

Cooper, Jessica. "Changing HR operating models." Strategic HR Review 14, no. 3 (June 8, 2015): 105–6. http://dx.doi.org/10.1108/shr-03-2015-0027.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Stuart, William B. "Checking Our Foundations: Matthews' Least Cost Models Revisited." Southern Journal of Applied Forestry 27, no. 1 (February 1, 2003): 30–35. http://dx.doi.org/10.1093/sjaf/27.1.30.

Full text

Abstract:

Abstract Logging in the U.S. South at the beginning of the twentieth century was an operating unit of manufacturing and therefore treated as a cost center. Around the middle of the century, it shifted to a service provided by standalone firms operating as “for profit” businesses. The engineering economy approach of cost control from the earlier era of company logging operations continues to be used by professionals. Increasing production to distribute “fixed costs” is a key element of many cost control approaches. The most common of these, the model for identifying the point of operation where average total cost per unit is minimized, exemplified by Matthews' road spacing model, is revisited considering the complexities of the modern operating environment and the competing objectives of land management, wood supply, and for-profit contractors. South. J. Appl. For. 27(1):30–35.

APA, Harvard, Vancouver, ISO, and other styles

3

Akkasi, Abbas, and Mohammad Ali Zeinaly. "Visualizing Operating Systems and Markov Models." International Journal of Computer Applications 119, no. 24 (June 20, 2015): 7–10. http://dx.doi.org/10.5120/21382-4371.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Thiessen, Avi, Karim El-Basyouny, and Suliman Gargoum. "Operating Speed Models for Tangent Segments on Urban Roads." Transportation Research Record: Journal of the Transportation Research Board 2618, no. 1 (January 2017): 91–99. http://dx.doi.org/10.3141/2618-09.

Full text

Abstract:

Information about operating speeds is essential to design better roads, model traffic emissions, and ensure design consistency while efficient and safe operations on roads are maintained. Therefore, understanding how different factors affect operating speeds and developing operating speed prediction models are critical research issues. Many studies have developed such models on rural roads and highways, but only a few studies have considered development of such models on urban roads and fewer still on tangential segments. This present study attempted to address these limitations by developing operating speed models with data from 249 tangential road segments in the city of Edmonton, Alberta, Canada. A generalized linear model was developed with panel data, and the primary aim was to explore the relationships between operating speeds on urban roads and features of the road environment. To study the impact of road elements on different road types, three models were created: one that combined arterial and collector locations, one for arterials only, and one for collector roads only. The results revealed that roads with sidewalks that were farther away from the road and with low object density or tree density were all associated with higher operating speeds. Locations with monolithic walks on both sides of the road had lower operating speeds. Furthermore, operating speeds decreased as access increased, while longer roads had higher operating speeds. One major takeaway was that the elements differed between road classes. The two variables, which stood out in that respect, were medians and bus stops.

APA, Harvard, Vancouver, ISO, and other styles

5

S. O. Chung and K. A. Sudduth. "SOIL FAILURE MODELS FOR VERTICALLY OPERATING AND HORIZONTALLY OPERATING STRENGTH SENSORS." Transactions of the ASABE 49, no. 4 (2006): 851–63. http://dx.doi.org/10.13031/2013.21725.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Woo, Tae-Gyeom, Sang-Hoon Lee, Hak-Jun Lee, and Young-Doo Yoon. "Flux Weakening Control Technique without Look-Up Tables for SynRMs Based on Flux Saturation Models." Electronics 9, no. 2 (January 27, 2020): 218. http://dx.doi.org/10.3390/electronics9020218.

Full text

Abstract:

This paper presents a flux weakening algorithm for synchronous reluctance motors (SynRMs) based on parameters estimated at standstill. Recently, flux saturated motors have been studied. Flux saturation models were identified and look-up tables were generated based on the saturation model for maximum torque per ampere (MTPA) and flux weakening operations. The operation with tables would degrade the accuracy of operating points when the table size is not enough. The proposed method implements a flux weakening operation without tables, and the operating points are determined with voltages and currents on operating points. Therefore, the accuracy can be maintained. In addition, the computation time to generate the tables is not needed, so the initial commissioning process can be reduced. The proposed method consists of two parts: the determination of a flux weakening region and the modification of current references. The flux weakening region is determined by the angle between direction vectors along the constant torque and voltage decreasing directions in the d-q axis current plane. After identifying the flux weakening region, the current references are modified for flux weakening according to the direction vector and appropriate magnitude. The direction and magnitude are determined by the operating point of the currents and magnitude of the output voltage, respectively. Using the flux saturation model for SynRMs, the flux weakening direction can be determined accurately. As a result, flux weakening can be performed precisely. The experimental results prove the validity of the proposed method.

APA, Harvard, Vancouver, ISO, and other styles

7

Emboaba Moreira, Mauricio, John O’Connell, and George Williams. "The Viability of Long-Haul, Low Cost Business Models." Journal of Air Transport Studies 2, no. 1 (January 1, 2011): 69–91. http://dx.doi.org/10.38008/jats.v2i1.106.

Full text

Abstract:

Recent events have confirmed the concerns that many within the aviation industry have held about the viability of the low cost business model for long-haul operations. This paper begins by reviewing the operating cost differences between low cost carriers (LCC) and legacy airlines in different regions of the world. This is followed by a summary of the various cost advantages of low cost carriers operating in short-haul markets. The main focus of the work, however, is a cost simulation involving the use of a Boeing 767-300 by both a LCC and a legacy carrier under varying operating assumptions. The research demonstrates that in none of the cases cited is the LCC cost advantage greater than 10%.

APA, Harvard, Vancouver, ISO, and other styles

8

Echaveguren, Tomás, Álvaro Díaz, and Sergio Vargas-Tejeda. "Operating speed models for horizontal reverse curves." Proceedings of the Institution of Civil Engineers - Transport 168, no. 6 (December 2015): 510–22. http://dx.doi.org/10.1680/jtran.13.00016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Kosinskiy, Mikhail, and Vladimir Shikhin. "Fuzzy models based operating reliability analysis method." IFAC Proceedings Volumes 45, no. 7 (2012): 191–95. http://dx.doi.org/10.3182/20120523-3-cz-3015.00038.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Zhang, Di, Qidong Peng, Junqiang Lin, Dongsheng Wang, Xuefei Liu, and Jiangbo Zhuang. "Simulating Reservoir Operation Using a Recurrent Neural Network Algorithm." Water 11, no. 4 (April 25, 2019): 865. http://dx.doi.org/10.3390/w11040865.

Full text

Abstract:

The reservoir is an important hydraulic engineering measure for human utilization and management of water resources. Additionally, a reasonable and effective reservoir operating plan is essential for realizing reservoir function. To explore the application of a deep learning algorithm on the field of reservoir operations, a recurrent neural network (RNN), long short-term memory (LSTM), and gated recurrent unit (GRU) are employed to predict outflows for the Xiluodu (XLD) reservoir. Meanwhile, this paper summarized the law of the effect of parameter setting on model performance compared to the simulation performance of three models, and analyzed the main factors that affect reservoir operation to provide the reference for future model of application research. Results show (1) the number of iterations and hidden nodes mainly influence the model precision, and the former has more effect than the latter, and the batch size mainly affects the calculated speed; (2) all three models can predict the reservoir outflow accurately and efficiently; (3) the operating decision generated by three models can implement the flood control and power generation goal of the reservoir and meet the operating regulation; and (4) under different hydrological periods, the influence factors of reservoir operation and their importance are different.

APA, Harvard, Vancouver, ISO, and other styles

11

Grzelak, Aleksander. "The income-assets relationship for farms operating under selected models in Poland." Agricultural Economics (Zemědělská ekonomika) 68, No. 2 (February 18, 2022): 59–67. http://dx.doi.org/10.17221/361/2021-agricecon.

Full text

Abstract:

The aim of this paper is to outline the relationship between income and assets when taking into account selected models of farms' functioning. The following farm models are examined: traditional, industrial, sustainable, and organic. Panel models were used that were based on the results of individual unpublished data for farms in Poland that undertook agricultural accounting according to the Farm Accounting Data Network (FADN) principles from 2004 to 2019. It was found that industrial farms had the clearest income-assets relationship, while traditional farms had the least clear relationship. The value of land, as a component of assets, was found to weaken the income-assets relationship. In consequence, the value of assets increased faster than income. Thus, the farmers are becoming wealthier in terms of the value of their assets, but this is not reflected in their income.

APA, Harvard, Vancouver, ISO, and other styles

12

SILVA, KETSON BRUNO DA, RAFAEL OLIVEIRA BATISTA, FRANCISCO DE OLIVEIRA MESQUITA, DANIELA DA COSTA LEITE COELHO, and WESLEY DE OLIVEIRA SANTOS. "EMPIRICAL MODELS FOR PERFORMANCE OF DRIPPERS APPLYING CASHEW NUT PROCESSING WASTEWATER." Revista Caatinga 29, no. 2 (June 2016): 405–14. http://dx.doi.org/10.1590/1983-21252016v29n217rc.

Full text

Abstract:

ABSTRACT: The objective of this work was to develop empirical models for hydraulic performance of drippers operating with cashew nut processing wastewater depending on operating time, operating pressure and effluent quality. The experiment consisted of two factors, types of drippers (D1=1.65 L h-1, D2=2.00 L h-1 and D3=4.00 L h-1), and operating pressures (70, 140, 210 and 280 kPa), with three replications. The flow variation coefficient (FVC), distribution uniformity coefficient (DUC) and the physicochemical and biological characteristics of the effluent were evaluated every 20 hours until complete 160 hours of operation. Data were interpreted through simple and multiple linear stepwise regression models. The regression models that fitted to the FVC and DUC as a function of operating time were square root, linear and quadratic, with 17%, 17% and 8%, and 17%, 17% and 0%, respectively. The regression models that fitted to the FVC and DUC as a function of operating pressures were square root, linear and quadratic, with 11%, 22% and 0% and the 0%, 22% and 11%, respectively. Multiple linear regressions showed that the dissolved solids content is the main wastewater characteristic that interfere in the FVC and DUC values of the drip units D1 (1.65 L h-1) and D3 (4.00 L h-1), operating at work pressure of 70 kPa (P1).

APA, Harvard, Vancouver, ISO, and other styles

13

YI, Chang-Yong, Han-Seong GWAK, and Dong-Eun LEE. "STOCHASTIC CARBON EMISSION ESTIMATION METHOD FOR CONSTRUCTION OPERATION." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 23, no. 1 (July 13, 2016): 137–49. http://dx.doi.org/10.3846/13923730.2014.992466.

Full text

Abstract:

Low carbon construction is an important operation management goal because greenhouse gas (GHG) reduction has become a global concern. Major construction resources that contribute GHG, such as equipment and labour, are being targeted to achieve this goal. The GHG emissions produced by the resources vary with their operating conditions. It is commendable to provide a statistical GHG emission estimation method that models the transitory nature of resource states at micro-scale of construction operations. This paper proposes a computational method called Stochastic Carbon Emission Estimation (SCE2) that measures the variability of GHG emissions. It creates construction operation models consisting of atomic work tasks, utilizes hourly equipment fuel consumption and hourly labourer respiratory rates that change according to their operating conditions classified into five categories, and identifies an optimal resource combination by trading off eco-economic performance metrics such as the amount of GHG emissions, operation completion time, operation completion cost, and productivity. The study is of value to researchers because SCE2 fill in a gap to eco-economic operation modelling and analysis tool which considers operating conditions at micro-scale of construction operation having many stochastic work tasks. This study is also relevance to practitioners because it allows project managers to achieve eco-economic goals while honouring predefined constraints associated with time and cost.

APA, Harvard, Vancouver, ISO, and other styles

14

Savoulides, N., K. S. Breuer, S. Jacobson, and F. F. Ehrich. "Low-Order Models for Very Short Hybrid Gas Bearings." Journal of Tribology 123, no. 2 (June 16, 2000): 368–75. http://dx.doi.org/10.1115/1.1308000.

Full text

Abstract:

A low-order model was created to analyze a small-scale gas bearing with a diameter of 4.1 mm, designed to spin at 2.4 million rpm. Due to microfabrication constraints, the bearing lies outside the standard operating space and stable operation is a challenge. The model is constructed by reference to Newton’s second law for the rotor and employs stiffness and damping coefficients predicted by other models. At any operating point it is able to predict (1) whether the journal can sustain stable operation, and (2) the whirling frequency of the journal. Analysis shows that the best way to operate the bearing is in a hybrid mode where the bearing relies on hydrostatics at low speeds and hydrodynamics at high speeds. However, in transitioning from hydrostatic to hydrodynamic operation, the model shows that the bearing is prone to instability problems and great care must be taken in scheduling the bearing pressurization system in the course of accelerating through low and intermediate rotational speeds.

APA, Harvard, Vancouver, ISO, and other styles

15

Wei, Chih Chiang. "Application of Pumping Operation Models for a Drainage System." Applied Mechanics and Materials 256-259 (December 2012): 2416–19. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2416.

Full text

Abstract:

A pumping operation model has been developed in urban areas caused by the storm runoff. The Chung-Kong pumping station in New Taipei City is used as a case study, where storm and operating records are used to train and verify the model’s performance. Historical records contain information of rainfall amounts, inner water levels, and pump and gate operating records in torrential rain events. The results show that the case with lag time of 15 min gives the better forecasted pumping discharge than other cases. The proposed predicting pumping model successfully addresses the problems of forecasted pumping discharge.

APA, Harvard, Vancouver, ISO, and other styles

16

Karlušić, Juraj, Mihael Cipek, Danijel Pavković, Juraj Benić, Željko Šitum, Zdravko Pandur, and Marijan Šušnjar. "Simulation Models of Skidder Conventional and Hybrid Drive." Forests 11, no. 9 (August 23, 2020): 921. http://dx.doi.org/10.3390/f11090921.

Full text

Abstract:

The paper presents a hypothetical conversion of a conventional cable skidder powertrain to its hybrid version. Simulations of skidder operation were made for two existing forest paths, based on the technical characteristics of the engine, transmission system and the characteristics of the winch. Fuel and time consumption were calculated per working cycle considering the operating conditions (slope, load mass). The model was then converted to a hybrid version by adding a battery energy storage system in parallel with the electrical power generator and by employing an energy management control strategy. The dimensions of the battery and the power generator were chosen based on the characteristics of the existing winch with the aim of completely taking over its operation. The management strategy was selected using the specific fuel consumption map. All simulations were repeated for the hybrid drive under the same operating conditions. The results show that fuel savings of around 13% can be achieved with the selected hybrid drive and steering strategy.

APA, Harvard, Vancouver, ISO, and other styles

17

Berman, Saul J. "Digital transformation: opportunities to create new business models." Strategy & Leadership 40, no. 2 (March 2, 2012): 16–24. http://dx.doi.org/10.1108/10878571211209314.

Full text

Abstract:

PurposeAccording to IBM research, companies seeking opportunities in an era of constant customer connectivity focus on two complementary activities: reshaping customer value propositions and transforming their operations using digital technologies for greater customer interaction and collaboration. This paper aims to address this issue.Design/methodology/approachThe paper explains that businesses aiming to generate new customer value propositions or transform their operating models need to develop a new portfolio of capabilities for flexibility and responsiveness to fast‐changing customer requirements.FindingsThe paper finds that engaging with customers at every point where value is created is what differentiates a customer‐centered business from one that simply targets customers well. Customer interaction in these areas often leads to open collaboration that accelerates innovation using online communities.Practical implicationsCompanies focused on fully reshaping the operating model optimize all elements of the value chain around points of customer engagement.Originality/valueThe article explains how companies with a cohesive plan for integrating the digital and physical components of operations can successfully transform their business models.

APA, Harvard, Vancouver, ISO, and other styles

18

Iranzi, Joseph, Hanam Son, Youngsoo Lee, and Jihoon Wang. "A Nodal Analysis Based Monitoring of an Electric Submersible Pump Operation in Multiphase Flow." Applied Sciences 12, no. 6 (March 9, 2022): 2825. http://dx.doi.org/10.3390/app12062825.

Full text

Abstract:

Electrical submersible pump (ESP) operation is compromised by free gas, resulting in premature pump failure and production losses in new wells. It is essential to detect the onset of abnormal operations. We develop a model that predicts abnormal ESP operation when the free gas level increases in the pump. The model compares operation parameters with the parameters of normal operating ranges; it shuts down the ESP when necessary. We used a Schlumberger PIPESIM software (version 2017.01) to perform nodal analysis technique; we tested the model using the other multiphase correlation model and field case studies (where the gas problem in ESP was reported). We employ a homogenous model to calculate the differential pump pressures at various gas volume fractions. Nodal analysis of the intake and discharge point predicted the commencement of abnormal ESP conditions and the associated parameters (critical gas fraction, minimum operating pump intake pressure, and pump discharge pressure). The model results were similar to other surging correlation models (e.g., Romero, Dunbar, Turpin, Cirilo, and Zhou models); they were also identical to field case studies. We identify three performance stability phases when an ESP is exposed to free gas. These are the normal and abnormal operating ranges, as well as the ESP shutdown condition. Modeling permits careful monitoring of ESP operations that can be compromised by free gas.

APA, Harvard, Vancouver, ISO, and other styles

19

Suri, Rajiv, and Kevin Otto. "Manufacturing System Robustness Through Integrated Modeling." Journal of Mechanical Design 123, no. 4 (August 1, 1999): 630–36. http://dx.doi.org/10.1115/1.1402129.

Full text

Abstract:

Robust design techniques are often applied to the design of manufacturing processes to determine the most robust operating points for a production system. However, such efforts have traditionally been focused on treating the output of each manufacturing operation in isolation. This approach ignores the fact that the sensitivity of each operation to input variation is a function of the operating point, which can only be changed in conjunction with the operating points of all other operations in that system. As such, applying robust design to each operation within a system individually does not guarantee lowest end-of-line variation. This is contrary to commonly held beliefs. What is needed instead is a method for conducting a system-wide parameter design where the operating points of each operation are optimized as a complete set to reduce final product variation. The logistics of such an integrated parameter design scheme become difficult or impossible on processes that may occur in different geographical locations. In this paper we outline the use of mathematical models to conduct system-wide parameter design. We demonstrate this technique on a model of a sheet stretch-forming manufacturing system. Through this example, we show that selecting operating points while considering the entire system results in a greater reduction in variation than Taguchi-style robust design conducted independently on each of the operations within the system.

APA, Harvard, Vancouver, ISO, and other styles

20

Zhang, Xue Hua. "Analysis of KATL Operation Simulated by TAAM." Applied Mechanics and Materials 713-715 (January 2015): 1601–4. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1601.

Full text

Abstract:

This objective of this research is to use Jeppesen’s Total Airspace and Airport Modelersimulator of airport and airspace operations (TAAM). TAAM has the capability to create models of airspace and airports, which makes it easy to planning, analysis, and making a decision. TAAM can help researchers evaluating the impact of changes to infrastructure, operations and schedules, after mimicking the airspace or airport into model.The simulation of this paper is going to imitate the operation of KATL in two different layouts with three different flight schedules based on a valid baseline model. In this case, the study is based on VFR operating condition, and operating towards west.

APA, Harvard, Vancouver, ISO, and other styles

21

Prodan, Dan, Anca Bucuresteanu, Tiberiu Dobrescu, and Adrian Motomancea. "Mathematical Models on the Closed Circuit Balancing Systems in Machine Tools." Applied Mechanics and Materials 859 (December 2016): 170–76. http://dx.doi.org/10.4028/www.scientific.net/amm.859.170.

Full text

Abstract:

In this paper we make a comparison between the most common balancing systems used in heavy duty machine tools and especially in CNC type ones. We introduce the systems with reducing valves, pumps with pressure regulator and the systems with accumulators assembled in closed circuit. For the latter we present calculation models used during operation under adiabatic transformations (operating times of seconds) or under isothermal transformations (operating times of minutes). There are also presented applications of these models for a gantry type milling machine and an AF type machine.

APA, Harvard, Vancouver, ISO, and other styles

22

Shtengelov, R. S. "On Operating Groundwater Wells in Grid-Scale Models." Moscow University Geology Bulletin 75, no. 1 (January 2020): 67–71. http://dx.doi.org/10.3103/s0145875220010123.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Getun, Galina, Yurij Butsenko, Olena Balina, Iryna Bezklubenko, and Andrii Solomin. "Diffusion models with accumulated characteristics when operating buildings." Strength of Materials and Theory of Structures, no. 102 (July 12, 2019): 243–51. http://dx.doi.org/10.32347/2410-2547.2019.102.243-251.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Castro, María, José F. Sánchez, and José A. Sánchez. "Operating speed models for two-lane rural highways." Proceedings of the Institution of Civil Engineers - Transport 165, no. 2 (May 2012): 107–18. http://dx.doi.org/10.1680/tran.2012.165.2.107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Miletić, Marija, Hrvoje Pandžić, and Dechang Yang. "Operating and Investment Models for Energy Storage Systems." Energies 13, no. 18 (September 4, 2020): 4600. http://dx.doi.org/10.3390/en13184600.

Full text

Abstract:

In the context of climate changes and the rapid growth of energy consumption, intermittent renewable energy sources (RES) are being predominantly installed in power systems. It has been largely elucidated that challenges that RES present to the system can be mitigated with energy storage systems (ESS). However, besides providing flexibility to intermittent RES, ESS have other sources of revenue, such as price arbitrage in the markets, balancing services, and reducing the cost of electricity procurement to end consumers. In order to operate the ESS in the most profitable way, it is often necessary to make optimal siting and sizing decisions, and to determine optimal ways for the ESS to participate in a variety of energy and ancillary service markets. As a result, many publications on ESS models with various goals and operating environments are available. This paper aims at presenting the results of these papers in a structured way. A standard ESS model is first outlined, and that is followed by a literature review on operational and investment ESS models at the transmission and distribution levels. Both the price taking and price making models are elaborated on and presented in detail. Based on the examined body of work, the paper is concluded with recommendations for future research paths in the analysis of ESS.

APA, Harvard, Vancouver, ISO, and other styles

26

Discetti, Paolo, Gianluca Dell'acqua, and Renato Lamberti. "Models of Operating Speeds for Low-Volume Roads." Transportation Research Record: Journal of the Transportation Research Board 2203, no. 1 (January 2011): 219–25. http://dx.doi.org/10.3141/2203-27.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Lee, Yun, Po-Wei Chen, and Eberhard O. Voit. "Analysis of operating principles with S-system models." Mathematical Biosciences 231, no. 1 (May 2011): 49–60. http://dx.doi.org/10.1016/j.mbs.2011.03.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Farber, Vanina Andrea, Susy Caballero, María Angela Prialé, and Rosa María Fuchs. "Social Enterprises in Lima: Notions and Operating Models." Journal of Entrepreneurship and Innovation in Emerging Economies 1, no. 1 (January 2015): 56–78. http://dx.doi.org/10.1177/2393957514554986.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Spivakovskyy, Sergiy, Tetiana Spivakovska, and Iryna Heiets. "Innovative business models for full cycle operating airlines." International Journal of Business Performance Management 20, no. 4 (2019): 356. http://dx.doi.org/10.1504/ijbpm.2019.10026923.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Heiets, Iryna, Sergiy Spivakovskyy, and Tetiana Spivakovska. "Innovative business models for full cycle operating airlines." International Journal of Business Performance Management 20, no. 4 (2019): 356. http://dx.doi.org/10.1504/ijbpm.2019.105246.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Ireland, Phil, Rod Case, John Fallis, Carl Van Dyke, Jason Kuehn, and Marc Meketon. "The Canadian Pacific Railway Transforms Operations by Using Models to Develop Its Operating Plans." Interfaces 34, no. 1 (February 2004): 5–14. http://dx.doi.org/10.1287/inte.1030.0055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Skripkin, S. G., D. A. Suslov, I. V. Litvinov, E. U. Gorelikov, M. A. Tsoy, and S. I. Shtork. "Comparative analysis of air and water flows in simplified hydraulic turbine models." Journal of Physics: Conference Series 2150, no. 1 (January 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2150/1/012001.

Full text

Abstract:

Abstract This article presents a comparative analysis of flow characteristics behind a hydraulic turbine runner in air and water. Swirling flow with a precessing vortex core (PVC) was investigated using a laser Doppler anemometer and pressure pulsation sensors. The experiments were conducted on aerodynamic and hydrodynamic test rigs over a wide range of hydraulic turbine operating conditions. Part-load modes of hydraulic turbine operation were investigated using the Fourier transform of pressure pulsations obtained from acoustic sensors. The features of the swirling flow were shown for the range of operating conditions from deep partl-load to overload.

APA, Harvard, Vancouver, ISO, and other styles

33

Simson, Scott A., Luis Ferreira, and Martin H. Murray. "Rail Track Maintenance Planning: An Assessment Model." Transportation Research Record: Journal of the Transportation Research Board 1713, no. 1 (January 2000): 29–35. http://dx.doi.org/10.3141/1713-05.

Full text

Abstract:

In Australian rail freight operations, railway track maintenance makes up between 25 and 35 percent of total train operating costs. Models have shown that track maintenance costs can be reduced by 5 to 10 percent through improved planning. The Track Maintenance Planning Model (TMPM) has been developed to deal with the track maintenance planning function in the medium to long term. In contrast to traditional models, which mainly use expert systems, TMPM simulates the impacts of railway track conditions and related maintenance work by using an existing track degradation model. Track condition data from that model are used to determine whether safety-related speed restrictions are needed and what immediate maintenance work may be required for safe train operation. TMPM outputs the net present value of the financial benefits of undertaking a given maintenance strategy compared with a base-case maintenance scenario. This approach has an advantage over current models in investigating what-if scenarios. The track engineer can assess the possible benefits of reduced operating costs from upgrading track infrastructure or from improving maintenance equipment. Track maintenance and train operating costs also can be simulated over time. The results of applying the model to a test track section using several different maintenance strategies are presented.

APA, Harvard, Vancouver, ISO, and other styles

34

Mathioudakis, K., A. Stamatis, A. Tsalavoutas, and N. Aretakis. "Computer Models for Education on Performance Monitoring and Diagnostics of Gas Turbines." International Journal of Mechanical Engineering Education 30, no. 3 (July 2002): 204–18. http://dx.doi.org/10.7227/ijmee.30.3.2.

Full text

Abstract:

The paper discusses how performance models can be incorporated in education on the subject of gas turbine performance monitoring and diagnostics. A particular performance model, built for educational purposes, is employed to demonstrate the different aspects of this process. The way of building a model is discussed, in order to ensure the connection between the physical principles used for diagnostics and the structure of the software. The first aspect discussed is model usage for understanding gas turbine behaviour under different operating conditions. Understanding this behaviour is essential, in order to have the possibility to distinguish between operation in ‘healthy’ and ‘faulty’ engine condition. A graphics interface is used to present information in different ways such as operating line, operating points on component maps, interrelation between performance variables and parameters. The way of studying faulty engine operation is then presented, featuring a novel comparison to existing simulation programs. Faults can be implanted into different engine components and their impact on engine performance studied. The notion of fault signatures on measured quantities is explained. The model has also a diagnostic capability, allowing the introduction of measurement data from faulty engines and providing a diagnosis, namely a picture of how the performance of engine components has deviated from a ‘healthy’ condition

APA, Harvard, Vancouver, ISO, and other styles

35

Nishino, Tomoya, Jie Ni, and Olivier Devuyst. "Transgenic Mouse Models." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 27, no. 6 (November 2007): 625–33. http://dx.doi.org/10.1177/089686080702700604.

Full text

Abstract:

The development of peritoneal dialysis has been paralleled by a growing interest in establishing suitable experimental models to better understand the functional and structural processes operating in the peritoneal membrane. Thus far, most investigations have been performed in rat and rabbit models, with mechanistic insights essentially based on intervention studies using pharmacological agents, blocking antibodies, or transient expression systems. Since the body size of a species is no longer a limiting factor in the performance of in vivo studies related to peritoneal dialysis, it has been considered that mice, particularly once they have been genetically modified, could provide an attractive tool to investigate the molecular mechanisms operating in the peritoneal membrane. The purpose of this review is to illustrate how investigators in peritoneal dialysis research, catching up with other fields of biomedical research, are increasingly taking advantage of mouse models to provide direct evidence of basic mechanisms involved in the major complications of peritoneal dialysis.

APA, Harvard, Vancouver, ISO, and other styles

36

Hung, Nguyen Ba, and Ocktaeck Lim. "Effects of Design Parameters on Operating Characteristics of an Electric Assisted Bicycle Using Fuel Cell." Sustainability 12, no. 11 (June 8, 2020): 4684. http://dx.doi.org/10.3390/su12114684.

Full text

Abstract:

A simulation study was conducted to examine the effects of design parameters on the operation of an electric power-assisted bicycle using fuel cell. Bicycle dynamic, electric motor and fuel cell models were built to depict operation of the electric bicycle. These models were solved by Matlab-Simulink to obtain the operating characteristics of the electric bicycle, such as power of fuel cell, propulsion force, moving distance and velocity. The simulation results in motion were compared to experimental results to validate the simulation models. The effects of the number of cells and hydrogen fuel pressure on the operation of the electric bicycle were investigated. In addition, the influences of slope grade on the operating characteristics of the electric-assisted bicycle and fuel cell were investigated in two cases: without and with fuel cell control. The simulation results show that the operating performance of the electric bicycle was improved when the number of cells was increased. The increase in hydrogen fuel pressure helped to increase the operating performance of the electric bicycle; however, this contribution was not significant. When fuel cell control was applied, the velocity of the electric assisted bicycle could be maintained at a stable value, in spite of changing slope grade.

APA, Harvard, Vancouver, ISO, and other styles

37

Prokopov, Artem, Viktor Prokhorov, Tetiana Kalashnikova, Tetiana Golovko, and Hanna Bohomazova. "Constructing a model for the automated operative planning of local operations at railroad technical stations." Eastern-European Journal of Enterprise Technologies 3, no. 3 (111) (June 30, 2021): 32–41. http://dx.doi.org/10.15587/1729-4061.2021.233673.

Full text

Abstract:

This paper has investigated the technology of forwarding local wagons at railroad technical stations and established the need to improve it given the extra downtime of local wagons. The main issue relates to the considerable combinatorial complexity of the tasks of operational planning. Another problem is that as part of the conventional approach, planning a station operation and planning a local operation at it is considered separately. Another planning issue is the lack of high-quality models for the preparation of initial data, in particular, data on the duration of technological operations, such as, for example, shunting operations involving local wagons forwarding. To resolve these issues, a new approach has been proposed, under which the tasks of operative planning of a technical station’s operation and its subsystem of local operations are tackled simultaneously, based on a single model. To this end, a mathematical model of vector combinatoric optimization has been built, which uses the criteria of total operating costs and wagon-hours spent at a station when forwarding local wagon flows, in the form of separate objective functions. Within this model, a predictive model was constructed in the form of a fuzzy inference system. This model is designed to determine the duration of shunting half-runs when executing the spotting/picking operations for delivering local wagons to enterprises’ goods sheds. The model provides for the accuracy level that would suffice at planning, in contrast to classical methods. A procedure has been devised for optimizing the planning model, which employs the modern genetic algorithm of vector optimization NSGA-III. This procedure is implemented in the form of software that makes it possible to build a rational operative plan for the operation of a technical station, including a subsystem of local operations, in graphic form, thereby reducing the operating costs by 5 % and the duration of maintenance of a local wagon by 8 %. The resulting effect could reduce the turnover time of a freight car in general on the railroad network, speed up the delivery of goods, and reduce the cost of transportation

APA, Harvard, Vancouver, ISO, and other styles

38

Jakubowski, Krzysztof, Jacek Paś, Stanisław Duer, and Jarosław Bugaj. "Operational Analysis of Fire Alarm Systems with a Focused, Dispersed and Mixed Structure in Critical Infrastructure Buildings." Energies 14, no. 23 (November 25, 2021): 7893. http://dx.doi.org/10.3390/en14237893.

Full text

Abstract:

The article presents issues regarding the impact of operating conditions on the functional reliability of representative fire alarm systems (FASs) in selected critical infrastructure buildings (CIB). FAS should operate correctly under variable environmental conditions. FASs ensure the safety of people and CIB. Operational measurements for 10 representative systems were conducted in order to determine the impact of environmental conditions on FAS reliability. Selected operational indices were also determined. The next stage involved developing two models of representative FASs and the availability, pre-ageing time and operating process security indices. Determining operational indices is a rational selection of FAS technical and organizational solutions that enables the reliability level to be increased. Identifying the course of the FAS operating process security hazard changes in individual system lines, particularly at the initial operation stage, enables people that supervise the operation to affect operating parameters on an ongoing basis. The article is structured in the following order: issue analysis, FAS power supply in CIB, operational test results, selected FAS operating process models, determination of operational and security indices, and conclusions.

APA, Harvard, Vancouver, ISO, and other styles

39

Stoyanov, K., and G. Zhelyazkov. "BUSINESS MODELS IN THE SOCIAL ECONOMY – REVIEW OF SUCCESSFUL PRACTICES." Trakia Journal of Sciences 17, Suppl.1 (2019): 176–80. http://dx.doi.org/10.15547/tjs.2019.s.01.029.

Full text

Abstract:

The social economy is a phenomenon that is gaining ever more significant dimensions, mainly because of its added value, which goes beyond measurable economic indicators. The role of enterprises operating in the social economy is also highly appreciated by the European Commission, which calculates their contribution to the European economy by more than 10% of its total. Because of the specificity and lack of specific legal rules, businesses use different business models to carry out their activities. The purpose of this study is to identify, define and evaluate the most commonly used business models of enterprises operating in the social economy, the so called third sector, analysing successful business practices. Using appropriate examples, including from Bulgaria, will be highlighted problematic issues for the functioning of social enterprises and some basic guidelines will be proposed to facilitate business operations in the social economy.

APA, Harvard, Vancouver, ISO, and other styles

40

Филимонова, Л. А., and Н. К. Скворцова. "Optimization models in project management through operating CASH FLOWS." Voprosy regionalnoj ekonomiki, no. 1(42) (March 12, 2020): 120–31. http://dx.doi.org/10.21499/2078-4023-2020-42-1-120-131.

Full text

Abstract:

В статье описаны результаты исследования методических и теоретических подходов к оценке денежного потока и причинно-следственных связей, определяющих направление и интенсивность его движения применительно к особенностям строительного бизнеса. Дано теоретическое обоснование научной целесообразности применения маржинального анализа (CVP-анализа (CastValueProfit - затраты, объем, прибыль)) в рамках системы учета «директ-костинг» (DirectCosting), как самого эффективного способа моделирования возможных ситуации в управлении проектами, способствующего предупреждению финансовых трудностей предприятия в условиях риска и неопределенности ситуации на подрядном рынке. The article describes the results of the study of methodical and theoretical approaches to the assessment of cash flow and cause-and-effect relationships, determining the direction and intensity of its movement in relation to the features of the construction business. The theoretical justification for the scientific feasibility of using margin analysis (CVP analysis (CastValue - costs, volume, profit) under the DirectCosting accounting system is the most effective way of modeling possible situation in the management of construction business projects, which helps to prevent the financial difficulties of the company in the face of risk and uncertainty of the situation in the contracting market.

APA, Harvard, Vancouver, ISO, and other styles

41

Chu, Justin, Chung-Ho Hsieh, Yi-Nuo Shih, Chia-Chun Wu, Anandakumar Singaravelan, Lun-Ping Hung, and Jia-Lien Hsu. "Operating Room Usage Time Estimation with Machine Learning Models." Healthcare 10, no. 8 (August 12, 2022): 1518. http://dx.doi.org/10.3390/healthcare10081518.

Full text

Abstract:

Effectively handling the limited number of surgery operating rooms equipped with expensive equipment is a challenging task for hospital management such as reducing the case-time duration and reducing idle time. Improving the efficiency of operating room usage via reducing the idle time with better scheduling would rely on accurate estimation of surgery duration. Our model can achieve a good prediction result on surgery duration with a dozen of features. We have found the result of our best performing department-specific XGBoost model with the values 31.6 min, 18.71 min, 0.71, 28% and 27% for the metrics of root-mean-square error (RMSE), mean absolute error (MAE), coefficient of determination (R2), mean absolute percentage error (MAPE) and proportion of estimated result within 10% variation, respectively. We have presented each department-specific result with our estimated results between 5 and 10 min deviation would be more informative to the users in the real application. Our study shows comparable performance with previous studies, and the machine learning methods use fewer features that are better suited for universal usability.

APA, Harvard, Vancouver, ISO, and other styles

42

Lavrov, A. G., and A. S. Shlyapnikov. "Mathematical Models of the Operating Modes of Power Autotransformers." Russian Electrical Engineering 90, no. 12 (December 2019): 757–62. http://dx.doi.org/10.3103/s1068371219120083.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Efremov, Denis Valentinovich, Viktoria Vladimirovna Kopach, Eugeny Valerievich Kornykhin, Viktor Vyacheslavovich Kuliamin, Alexander Konstantinovich Petrenko, Alexey Vladimirovich Khoroshilov, and Ilya Viktorovich Shchepetkov. "Runtime Verification of Operating Systems Based on Abstract Models." Proceedings of the Institute for System Programming of the RAS 33, no. 6 (2021): 15–26. http://dx.doi.org/10.15514/ispras-2021-33(6)-2.

Full text

Abstract:

High complexity of a modern operating system (OS) requires to use complex models and high-level specification languages to describe even separated aspects of OS functionality, e.g., security functions. Use of such models in conformance verification of modeled OS needs to establish rather complex relation between elements of OS implementation and elements of the model. In this paper we present a method to establish and support such a relation, which can be effectively used in testing and runtime verification/monitoring of OS. The method described was used successfully in testing and monitoring of Linux OS core components on conformance to Event-B models.

APA, Harvard, Vancouver, ISO, and other styles

44

Кузнецов, Виталий Вадимович, and Анатолий Васильевич Николенко. "Models of operating asynchronous engines at poor-quality electricity." Eastern-European Journal of Enterprise Technologies 1, no. 8(73) (February 23, 2015): 37. http://dx.doi.org/10.15587/1729-4061.2015.36755.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Plotz. "Operating at a Loss: Nominal Values and Mechanical Models." Victorian Studies 62, no. 2 (2020): 268. http://dx.doi.org/10.2979/victorianstudies.62.2.14.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

McAllister, Pat. "Creating operational alpha? Operating models for real estate management." Property Management 38, no. 4 (July 14, 2020): 565–83. http://dx.doi.org/10.1108/pm-02-2020-0009.

Full text

Abstract:

PurposeFocussing on the UK’s institutional real estate universe, this paper analyses variations in the operational management of real estate investment portfolios. For the main categories of institutional investors, the key tasks in real estate operational management, and the ways in which these tasks are typically bundled and categorised by investment managers are reviewed. Three broad operational management models are outlined. Case studies of real estate operational management models in practice are discussed.Design/methodology/approachThe research approach is primarily descriptive, drawing upon illustrative investor case studies.FindingsA range of operating models are identified for managing real estate investment portfolios. Specialists real estate investors tend to have highly vertically integrated operating models viewing most operational management functions as core operational capabilities. Multi-asset owners tend to have a vertically disintegrated operating model outsourcing fund, asset, property and facilities management. Investing institutions such as fund houses and specialist real estate investment advisors seem to have converged upon a common hybrid operating model with high margin, analytical functions such as fund and asset management being insourced and low margin, routine functions such as property and facilities management being outsourced.Originality/valueDespite the size of the global, institutional real estate investment universe (estimated by DTZ to be worth more than USD 13.6 trillion in 2015), the topic of how (and how effectively) these assets are managed by institutional investors has attracted very little attention from the real estate research community. This paper provides some initial analysis and insights into operational management models for real estate investment portfolios in the contemporary real estate investment management landscape.

APA, Harvard, Vancouver, ISO, and other styles

47

Alhazmi, O. H., and Y. K. Malaiya. "Application of Vulnerability Discovery Models to Major Operating Systems." IEEE Transactions on Reliability 57, no. 1 (March 2008): 14–22. http://dx.doi.org/10.1109/tr.2008.916872.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Zhao, Zhong, Xiaohua Xia, Jingchun Wang, Jian Gu, and Yihui Jin. "Nonlinear dynamic matrix control based on multiple operating models." Journal of Process Control 13, no. 1 (February 2003): 41–56. http://dx.doi.org/10.1016/s0959-1524(02)00012-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Grunkemeier, Gary L., and Ruyun Jin. "Receiver operating characteristic curve analysis of clinical risk models." Annals of Thoracic Surgery 72, no. 2 (August 2001): 323–26. http://dx.doi.org/10.1016/s0003-4975(01)02870-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Hetherington, David. "Book Publishing: New Environments Call for New Operating Models." Publishing Research Quarterly 30, no. 4 (September 6, 2014): 382–87. http://dx.doi.org/10.1007/s12109-014-9379-y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Operating models'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles