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Article
Publication date: 15 July 2022

Mehrnaz Ahmadi and Mehdi Khashei

The purpose of this paper is to propose a new linear-nonlinear data preprocessing-based hybrid model to achieve a more accurate result at a lower cost for wind power…

Abstract

Purpose

The purpose of this paper is to propose a new linear-nonlinear data preprocessing-based hybrid model to achieve a more accurate result at a lower cost for wind power forecasting. For this purpose, a decomposed based series-parallel hybrid model (PKF-ARIMA-FMLP) is proposed which can model linear/nonlinear and certain/uncertain patterns in underlying data simultaneously.

Design/methodology/approach

To design the proposed model at first, underlying data are divided into two categories of linear and nonlinear patterns by the proposed Kalman filter (PKF) technique. Then, the linear patterns are modeled by the linear-fuzzy nonlinear series (LLFN) hybrid models to detect linearity/nonlinearity and certainty/uncertainty in underlying data simultaneously. This step is also repeated for nonlinear decomposed patterns. Therefore, the nonlinear patterns are modeled by the linear-fuzzy nonlinear series (NLFN) hybrid models. Finally, the weight of each component (e.g. KF, LLFN and NLFN) is calculated by the least square algorithm, and then the results are combined in a parallel structure. Then the linear and nonlinear patterns are modeled with the lowest cost and the highest accuracy.

Findings

The effectiveness and predictive capability of the proposed model are examined and compared with its components, based models, single models, series component combination based hybrid models, parallel component combination based hybrid models and decomposed-based single model. Numerical results show that the proposed linear-nonlinear data preprocessing-based hybrid models have been able to improve the performance of single, hybrid and single decomposed based prediction methods by approximately 66.29%, 52.10% and 38.13% for predicting wind power time series in the test data, respectively.

Originality/value

The combination of single linear and nonlinear models has expanded due to the theory of the existence of linear and nonlinear patterns simultaneously in real-world data. The main idea of the linear and nonlinear hybridization method is to combine the benefits of these models to identify the linear and nonlinear patterns in the data in series, parallel or series-parallel based models by reducing the limitations of the single model that leads to higher accuracy, more comprehensiveness and less risky predictions. Although the literature shows that the combination of linear and nonlinear models can improve the prediction results by detecting most of the linear and nonlinear patterns in underlying data, the investigation of linear and nonlinear patterns before entering linear and nonlinear models can improve the performance, which in no paper this separation of patterns into two classes of linear and nonlinear is considered. So by this new data preprocessing based method, the modeling error can be reduced and higher accuracy can be achieved at a lower cost.

Details

Journal of Modelling in Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1746-5664

Keywords

Article
Publication date: 19 June 2009

J. Sharana Basavaraja, Sathish Sharma and Sathish Jain

The non‐recessed hybrid journal bearings of cylindrical type, when operating at higher rotational speeds can suffer self‐exited vibrations(oil‐whirl Instability), which…

Abstract

Purpose

The non‐recessed hybrid journal bearings of cylindrical type, when operating at higher rotational speeds can suffer self‐exited vibrations(oil‐whirl Instability), which can cause excessive rotor motion causing bearing and sometimes total machine failure. The multi‐lobe journal bearing exhibits better stability as well as a superior capability to suppress oil‐whirl. The paper aims to present a theoretical study pertaining to a two‐lobe hole‐entry hybrid journal bearing by considering the combined influence of surface roughness and journal misalignment on the performance of the bearing.

Design/methodology/approach

The average Reynolds equation governing the flow of lubricant in the clearance space between the rough bearing surfaces together with the equation of flow through a capillary restrictor has been solved using FEM. The bearing performance characteristics have been simulated for a two‐lobe hole‐entry hybrid journal bearing for the various values of offset factor, restrictor design parameter, surface roughness parameter, surface pattern parameter and journal misalignment parameters.

Findings

The two‐lobe hole‐entry hybrid journal bearing system with an offset factor greater than one indicates significant improvement of the order of 15‐25 percent in the values of direct stiffness and direct damping coefficients compared to a circular hole‐entry hybrid journal bearing system. Also the lubricant flow of a two‐lobe hole‐entry hybrid journal bearing is reduced by 25 percent vis‐à‐vis circular bearing.

Originality/value

The present work is original of its kind, in case of two‐lobe hole‐entry hybrid journal bearing. The results are quite useful for the bearing designer.

Details

Industrial Lubrication and Tribology, vol. 61 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 30 September 2014

C. Pornet, S. Kaiser, A.T. Isikveren and M. Hornung

The aim of this paper is to assess the potential of fuel-battery hybrid narrow-body (180PAX) transport aircraft according to different design ranges for an…

1008

Abstract

Purpose

The aim of this paper is to assess the potential of fuel-battery hybrid narrow-body (180PAX) transport aircraft according to different design ranges for an entry-into-service (EIS) of 2035.

Design/methodology/approach

The philosophy used in the design of the twin-engine fuel-battery hybrid concept is to use the power of an electric motor during cruise to drive a single propulsive device, whereas the other one is powered conventionally by an advanced gas turbine. A methodology for the sizing and performance assessment of hybrid energy aircraft was previously proposed by the authors. Based on this methodology, the overall sizing effects at aircraft level are considered to size the hybrid aircraft to different range applications. To evaluate the hybrid concept, performance was contrasted against a conventional aircraft projected to EIS 2035 and sized for identical requirements. Additionally, sensitivity of the prospects against different battery technology states was analysed.

Findings

The best suited aircraft market for the application of the fuel-battery hybrid transport aircraft concept considered is the regional segment. Under the assumption of a battery-specific energy of 1.5 kWh/kg, block fuel reduction up to 20 per cent could be achieved concurrently with a gate-to-gate neutral energy consumption compared to an advanced gas-turbine aircraft. However, a large increase in maximum take-off weight (MTOW) occurs resulting from battery weight, the additional electrical system weight, and the cascading sizing effects. It strongly counteracts the benefit of the hybrid-electric propulsion technology used in this concept for lower battery-specific energy and for longer design ranges.

Practical implications

The findings will contribute to the evaluation of the feasibility and impact of hybrid energy transport aircraft as potential key enablers of the European and US aeronautical program goals towards 2035.

Originality/value

The paper draws its value from the consideration of the overall sizing effects at aircraft level and in particular the impact of the hybrid-electric propulsion system to investigate the prospects of fuel-battery hybrid narrow-body transport aircraft sized at different design ranges.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 86 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 January 1989

N. Sinnadurai

In order to identify and quantify the size and shape of the rapidly changing complexion of the market for hybrid microelectronics, in 1987 ISHM launched a survey in Europe…

Abstract

In order to identify and quantify the size and shape of the rapidly changing complexion of the market for hybrid microelectronics, in 1987 ISHM launched a survey in Europe of the market for thin‐film, thick‐film and surface‐mount‐on‐PCB hybrids for the periods 1980, 1986 and 1990. The survey aimed to obtain a hierarchical breakdown of the markets also into technology and application sectors. The general findings are reported. The credibility and quantity of the survey are considered in the context of the market for electronic equipment in Europe for 1987 and 1990. In electronics there is a continuing pressure to reduce prices and therefore adjustments should not be made for inflation. A growth in market value is thus a true reflection of a larger growth in market volume and a continuing increase in complexity. Thus, the 11% CAGR for 1986–1990 reflects a growth in equipment volumes of 20% over the 4 year period. Manufacturers will have to design and build increasingly complex circuits at a higher throughput and lower cost, at an increasing pace. It is not a business for faint hearts. Clearly the growth potential for the hybrid microelectronics market should be considered in the context of the equipment market, in order to judge the relative growth. In order to distinguish between the hybrid and PCB industries, the survey has aimed to estimate the growth in the developing market for hybrids using substrates up to 6 in. × 4 in. (Eurocard), not including the larger SMAs on PCBs for which there is a huge market growth potential. The immediate opportunity is from miniaturisation and cost reduction using hybrid microelectronics. The major push in technological emphasis in modern hybrids comes from the need for high‐density interconnection to support increasingly complex VLSI in high‐pin‐count surface‐mount micropackages and high‐performance substrates to support VHSIC and high‐performance circuits. Hence there is a major shift in hybrid microelectronics technology emphasis towards high‐density surface‐mount assemblies on PCB and other organic substrates. The total hybrid market sub‐divided among the basic three technologies reveals this emphasis. The portents are clear, and those who intend to succeed, or even simply survive, need to be aware of the shift in emphasis and prepare to diversify or establish strengths in niche applications.

Details

Microelectronics International, vol. 6 no. 1
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 30 September 2013

Haiou Zhang, Xiangping Wang, Guilan Wang and Yang Zhang

The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the…

1556

Abstract

Purpose

The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the manufacturing principle and show the advantages of this method.

Design/methodology/approach

This paper introduces the hybrid manufacturing principle and devices first. Then, the key parameters of hybrid manufacturing process are studied by contrast experiments. The results of comparisons of manufacturing accuracy, microstructure and tensile test between freeform fabricated parts and hybrid manufactured parts show the advantages of this new direct manufacturing method.

Findings

The experiments results show that the accuracy of hybrid manufacturing method is improved obviously comparing with arc-based freeform deposition manufacturing method; the microstructure of the hybrid manufacturing part turns into cellular crystal instead of dendrite; the tensile strength of the part increases by 33 percent and the tensile deformation improved more than two times.

Originality/value

The paper presents a new hybrid direct metal manufacturing method for the first time. The hybrid manufacturing devices are developed. The experiments results show that the hybrid manufacturing method can be used on directly fabricating large metal components with outstanding quality, efficiency and low cost. The application prospect is great.

Details

Rapid Prototyping Journal, vol. 19 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 30 August 2013

M.P. Jenarthanan and R. Jeyapaul

The purpose of this paper is to report the preparation, characterisation and machinability of resin hybrid GFRP composites, which are made of glass fibre and the mixture…

Abstract

Purpose

The purpose of this paper is to report the preparation, characterisation and machinability of resin hybrid GFRP composites, which are made of glass fibre and the mixture of epoxy & polyester resin.

Design/methodology/approach

Resin hybrid GFRP laminates containing 0, 20 and 40wt% of polyester resin with the epoxy resin are prepared by conventional hand layup technique using glass fibre as the reinforcement. The variation of break load and shear strength for three different combinations of epoxy and polyester resin are studied by ASTM. A plan of experiment based on Taguchi was established with prefixed cutting parameters and the machining was performed. A stylus type profilometer to examine the surface roughness and shop microscope to examine the delamination of resin hybrid GFRP laminates were used. An analysis of variance (ANOVA) was performed to investigate the cutting characteristics of resin hybrid GFRP composite materials using solid carbide end mill. The correlation was obtained by multiple‐variable linear regression using Minitab 14 software.

Findings

Taguchi analysis reveals that the resin hybrid GFRP laminate provides better machinability in terms of surface roughness and delamination when compared to homogenous GFRP laminates (pure epoxy resin). Polyester resin enhances the machinability of the GFRP laminates.

Research limitations/implications

The machinability of the resin hybrid GFRP laminates can be improved further by modifying the polyester resin percentage.

Originality/value

The resin hybrid GFRP laminates so developed can be used in aircraft and aerospace applications to increase the shear and work of fracture properties.

Details

Pigment & Resin Technology, vol. 42 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 16 August 2011

Akihiro Fukushima

The purpose of this paper is to propose two hybrid forecasting models which integrate available ones. A hybrid contaminated normal distribution (CND) model accurately…

Abstract

Purpose

The purpose of this paper is to propose two hybrid forecasting models which integrate available ones. A hybrid contaminated normal distribution (CND) model accurately reflects the non‐normal features of monthly S&P 500 index returns, and a hybrid GARCH model captures a serial correlation with respect to volatility. The hybrid GARCH model potentially enables financial institutions to evaluate long‐term investment risks in the S&P 500 index more accurately than current models.

Design/methodology/approach

The probability distribution of an expected investment outcome is generated with a Monte Carlo simulation. A taller peak and fatter tails (kurtosis), which the probability distribution of monthly S&P 500 index returns contains, is produced by integrating a CND model and a bootstrapping model. The serial correlation of volatilities is simulated by applying a GARCH model.

Findings

The hybrid CND model can simulate the non‐normality of monthly S&P 500 index returns, while avoiding the influence of discrete observations. The hybrid GARCH model, by contrast, can simulate the serial correlation of S&P 500 index volatilities, while generating fatter tails. Long‐term investment risks in the S&P 500 index are affected by the serial correlation of volatilities, not the non‐normality of returns.

Research limitations/implications

The hybrid models are applied only to the S&P 500 index. Cross‐sectional correlations among different asset groups are not examined.

Originality/value

The proposed hybrid models are unique because they combine available ones with a decision tree algorithm. In addition, the paper clearly explains the strengths and weaknesses of existing forecasting models.

Details

The Journal of Risk Finance, vol. 12 no. 4
Type: Research Article
ISSN: 1526-5943

Keywords

Article
Publication date: 1 June 2022

Curt A. Gilstrap, Srishti Srivastava and Cristina M. Gilstrap

This study aims to investigate the ways mobile hybrid team members make sense of their teamwork.

Abstract

Purpose

This study aims to investigate the ways mobile hybrid team members make sense of their teamwork.

Design/methodology/approach

Using surveys, this study examined 579 US-based mobile hybrid team members as they discussed their professional team activities. Leximancer software determined, through frequency and co-occurrence analysis of survey-resulting unstructured data sets, the themes mobile hybrid team members use to make sense of their teamwork.

Findings

Participants included the concepts Team, Technology, Communication, Context and Time relative to 25 specific content themes within their talk about teamwork. While thematic clusters such as Team and Communication were densely packed, Technology and Time co-occurred more widely in support of other content themes within the mobile hybrid team member data set. This suggests mobile technologies pervade mobile hybrid team members’ sensemaking about their work.

Originality/value

A first of its kind inquiry into how mobile hybrid team members make sense of work and performance within their teams, this study highlights the need to explore further how mobile hybrid team members frame and enact technological processes as integral to their organizational work and team outcomes.

Details

Team Performance Management: An International Journal, vol. 28 no. 5/6
Type: Research Article
ISSN: 1352-7592

Keywords

Book part
Publication date: 14 November 2017

Rick Colbourne

Indigenous entrepreneurship and hybrid venture creation represents a significant opportunity for Indigenous peoples to build vibrant Indigenous-led economies that support…

Abstract

Indigenous entrepreneurship and hybrid venture creation represents a significant opportunity for Indigenous peoples to build vibrant Indigenous-led economies that support sustainable economic development and well-being. It is a means by which they can assert their rights to design, develop and maintain Indigenous-centric political, economic and social systems and institutions. In order to develop an integrated and comprehensive understanding of the intersection between Indigenous entrepreneurship and hybrid ventures, this chapter adopts a case study approach to examining Indigenous entrepreneurship and the underlying global trends that have influenced the design, structure and mission of Indigenous hybrid ventures. The cases present how Indigenous entrepreneurial ventures are, first and foremost, hybrid ventures that are responsive to community needs, values, cultures and traditions. They demonstrate that Indigenous entrepreneurship and hybrid ventures are more successful when the rights of Indigenous peoples are addressed and when these initiatives are led by or engage Indigenous communities. The chapter concludes with a conceptual model that can be applied to generate insights into the complex interrelationships and interdependencies that influence the formation of Indigenous hybrid ventures and value creation strategies according to three dimensions: (i) the overarching dimension of indigeneity and Indigenous rights; (ii) indigenous community orientations and (iii) indigenous hybrid venture creation considerations.

Book part
Publication date: 7 December 2020

Silvia Dorado

This chapter explores how hybrid organizations navigate the challenges (and opportunities) associated with advancing unconventional logic combinations. It draws from a…

Abstract

This chapter explores how hybrid organizations navigate the challenges (and opportunities) associated with advancing unconventional logic combinations. It draws from a study of the 180-year history of sheltered workshops in the United States. Sheltered workshops are hybrids that combine social and commercial logics to provide gainful employment to individuals with disabilities. This chapter theorizes a connection between the governance system – that is, country-based social norms and regulatory settlements – framing hybrids and the agency that allows them the discretion required to advance unconventional combinations. It introduces the term hybrid agency to describe this connection and identifies four types: upstream, midstream, downstream, and crosscurrent. Upstream agency draws from the entrepreneurial vision of charismatic founders. It allows hybrids the discretion to advance unconventional logic combinations in unsupportive times, but it also requires them to observe certain dominant cultural norms. Midstream agency draws from hybrids’ adaptation and advocacy skills and resources in periods of historical change. It allows access to resources and legitimacy for unconventional combinations. Downstream agency draws from organizational slack possible in supportive times. Slack eases tensions and tradeoffs between conflicting logics but may also fuel mission drift. Finally, crosscurrent agency also draws from hybrids’ adaptation and advocacy skills and resources. It provides hybrids with the opportunity to grapple with challenges in periods of contestation.

Details

Organizational Hybridity: Perspectives, Processes, Promises
Type: Book
ISBN: 978-1-83909-355-5

Keywords

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