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  • Öğe
    Investigating the value of reducing errors in inventory information from a supply chain perspective
    (Emerald Group Publishing Limited, 2015) Sarı, Kazım
    Purpose - The purpose of this paper is to investigate the value of reducing errors in inventory information from a supply chain perspective. To this end, the benefits of reducing errors in inventory information are compared with those of lead time reduction and supply chain collaboration. Design/methodology/approach -A simulation model is constructed to perform the analysis. Findings - Results show that lead time reduction is the most important strategy for a supply chain in reducing total supply chain cost. In terms of customer service level, on the other hand, strategy of reducing errors in inventory information is observed as the most considerable strategy. However, the results for supply chain collaboration are somewhat unexpected. Namely, in spite of its popularity, supply chain collaboration provides very limited contribution to the supply chain. Practical implications - This research provides useful knowledge for the managers of a business enterprise in prioritizing various supply chain strategies. Originality/value - In supply chain management literature, greater emphasis is given to lead time reduction and supply chain collaboration than dealing with errors in inventory information. This research makes it clear that errors in inventory information should not be underestimated.
  • Öğe
    Internet of things and aviation: a bibliometric and visualization analysis
    (Emerald Group Publishing Ltd, 2023) Burak, Mehmet Fatih; Kusbeci, Polathan
    PurposeConsidering both the current opportunities of the Internet of things (IoT) and aviation, as well as the potential opportunities they may offer for the future, it is understood that they are among the important issues that need to be examined in the literature. This study aims to provide an idea by conducting bibliometric and visualization analyses of the current trends and development opportunities of IoT and aviation.Design/methodology/approachIn this study, descriptive and bibliometric analyses within the framework of co-author, co-citation, bibliographic coupling, and keyword co-occurrence analysis were carried out for publications found to be published between 2007 and 2023 in the Web of Science (WoS) database related to IoT and aviation. VOSviewer (ver. 1.6.18) program and the Biblioshiny application were used to create bibliometric networks and provide visualization.FindingsAs a result of some descriptive and visualization analyses, the current trend of publications on IoT and aviation and future publication opportunities has been revealed. It has been understood that the subject of IoT and aviation is one of the subjects whose number of publications has increased in recent years and has not yet fully matured in terms of the number of publications and has the potential to make new publications.Originality/valueIn this study, bibliometric analysis of IoT and aviation, which could not be found examined before in the literature, and the creation of existing bibliometric networks by visualizing were carried out.
  • Öğe
    (Architectural) design research through reflection: a sub-approach under research by design
    (Emerald Group Publishing Ltd, 2022) Uzunkaya, Asli; Paker Kahvecioglu, Nurbin
    Purpose This study is based on a research approach proposal aiming to reveal tacit knowledge that shapes architectural design processes through subjective accumulations and tools. With the premise that design embodies tacit and personal knowledge, it proposes an alternative way to decipher this subjective medium. Design/methodology/approach The proposed research approach, (architectural) design research through reflection, basically belongs to research by design method and narrowed in the focus of reflection. It enables to study how tacit knowledge functions within processes of architectural design without being its very subject. The proposal and the product of the approach, revealing diagram, are developed through the architect's tools and the involvement of the researchers in the process. It is also supported by a conceptual basis created from literature on reflection. Findings By means of the proposal, the reflective accumulation of the subjects, that is, the tacit knowledge, is investigated in relation to practice. The revealing diagram is presented as a tool through which relations can be interpreted within the framework of subjects. It is a tool by which the subjects, tools and processes of the architectural design product can be analysed. Originality/value The study contributes to architectural research by shifting the perspective on reflective knowledge that shapes design processes.
  • Öğe
    Posture labeling based gesture classification for Turkish sign language using depth values
    (Emerald Group Publishing Ltd, 2016) Saykol, Ediz; Ture, Halit Talha; Sirvanci, Ahmet Mert; Turan, Mert
    Purpose - The purpose of this paper to classify a set of Turkish sign language (TSL) gestures by posture labeling based finite-state automata (FSA) that utilize depth values in location-based features. Gesture classification/recognition is crucial not only in communicating visually impaired people but also for educational purposes. The paper also demonstrates the practical use of the techniques for TSL. Design/methodology/approach - Gesture classification is based on the sequence of posture labels that are assigned by location-based features, which are invariant under rotation and scale. Grid-based signing space clustering scheme is proposed to guide the feature extraction step. Gestures are then recognized by FSA that process temporally ordered posture labels. Findings - Gesture classification accuracies and posture labeling performance are compared to k-nearest neighbor to show that the technique provides a reasonable framework for recognition of TSL gestures. A challenging set of gestures is tested, however the technique is extendible, and extending the training set will increase the performance. Practical implications - The outcomes can be utilized as a system for educational purposes especially for visually impaired children. Besides, a communication system would be designed based on this framework. Originality/value - The posture labeling scheme, which is inspired from keyframe labeling concept of video processing, is the original part of the proposed gesture classification framework. The search space is reduced to single dimension instead of 3D signing space, which also facilitates design of recognition schemes. Grid-based clustering scheme and location-based features are also new and depth values are received from Kinect. The paper is of interest for researchers in pattern recognition and computer vision.
  • Öğe
    A mathematical model for erosive abrasive wear analysis by using abrasive size and material hardness
    (Emerald Group Publishing Ltd, 2023) Kosa, Ergin; Goksenli, Ali
    Purpose - Erosion and abrasion are the prominent wear mechanisms reducing the lifetime of machine components. Both wear mechanisms are playing a role meanwhile, generating a synergy, leading to a material removal on the target. The purpose of study is to create a mathematical expression for erosive abrasive wear.Design/methodology/approach - -Many factors such as environmental cases and material character have an influence in erosive abrasive wear. In the work, changes in abrasive size and material hardness have been analyzed. As an abrasive particle, quartz sand has been used. All tests have been done in 20 wt.% slurry. Heat treatment has been applied to different steel specimens (steel grades C15, St 37 and Ck45) to change hardness value, which ranged from 185 to 880 Vickers hardness number.Findings - After the four-hour test, it is determined that by an increase in abrasive size and decrease in material hardness, wear rate increases. Worn surfaces of the targets have been examined to figure out the wear mechanisms at different conditions under scanning electron microscopy. The results indicate that by an increase in material hardness, the number and diameter of micro-craters on the worn surfaces decrease. The diameters of micro-craters have been about 3-8 mu m in hard materials and about 120-140 mu m in soft materials.Research limitations/implications - It is determined that by an increase in abrasive size and decrease in material hardness, wear rate increases. The results indicate that by an increase in material hardness, the number and diameter of micro-craters on the worn surfaces decrease.Practical implications - The study enables to indicate the dominant factor in worn steel used in mechanical components.Originality/value - After analyzing the test results, a novel mathematical expression, considering both abrasive size and material hardness, has been developed.
  • Öğe
    Public debt forecasts and machine learning: the Italian case
    (Emerald Group Publishing Ltd, 2023) Sica, Edgardo; Altinbas, Hazar; Marini, Gaetano Gabriele
    PurposePublic debt forecasts represent a key policy issue. Many methodologies have been employed to predict debt sustainability, including dynamic stochastic general equilibrium models, the stock flow consistent method, the structural vector autoregressive model and, more recently, the neuro-fuzzy method. Despite their widespread application in the empirical literature, all of these approaches exhibit shortcomings that limit their utility. The present research adopts a different approach to public debt forecasts, that is, the random forest, an ensemble of machine learning.Design/methodology/approachUsing quarterly observations over the period 2000-2021, the present research tests the reliability of the random forest technique for forecasting the Italian public debt.FindingsThe results show the large predictive power of this method to forecast debt-to-GDP fluctuations, with no need to model the underlying structure of the economy.Originality/valueCompared to other methodologies, the random forest method has a predictive capacity that is granted by the algorithm itself. The use of repeated learning, training and validation stages provides well-defined parameters that are not conditional to strong theoretical restrictions This allows to overcome the shortcomings arising from the traditional techniques which are generally adopted in the empirical literature to forecast public debt.
  • Öğe
    Antecedents and consequences of organizational ambidexterity: the moderating role of networking
    (Emerald Group Publishing Ltd, 2018) Gunsel, Ayse; Altindag, Erkut; Keceli, Selva Kilic; Kitapci, Hakan; Hiziroglu, Mahmut
    Purpose - The purpose of this paper is to develop a holistic model regarding the antecedents and consequences of organizational ambidexterity in the context of small and medium sized enterprises (SMEs), particularly for developing countries such as Turkey. Moreover, this paper also aims to reveal the moderating role of networking between organizational ambidexterity and firm performance. Design/methodology/approach - By studying 105 SMEs engaged in small business and technology development centers (SBTDCs), structural equation modeling through SmartPLS is executed. Findings - The findings show that: discipline and support positively influence the formation and the maintenance of organizational ambidexterity; organizational ambidexterity significantly contributes to firm performance; and the greater the networking the greater the relationship between exploitation capability and firm performance. Originality/value - To date, there has been no systematic attempt in the extant literature to develop a holistic manner of organizational ambidexterity, with its antecedents and consequences in the context of SMEs in general, in SMEs of a developing country, Turkey in particular. Moreover, the moderating role of networking between organizational ambidexterity and a firm's performance has never been examined.
  • Öğe
    Recommendation matters: how does your social capital engage you in eWOM?
    (Emerald Group Publishing Ltd, 2022) Baykal, Bilge; Karaca, Ozlem Hesapci
    Purpose The purpose of this study is to contribute to the existing knowledge on two aspects. First, the authors introduce a conceptual model based on the social capital theory (SCT) to understand the mechanisms through which social capital factors affect consumers' electronic word-of-mouth (eWOM) engagement and purchase intentions via social network sites (SNSs). Second, the present study empirically tests and validates the proposed relationships that delineate social capital dimensions as crucial precursors of eWOM engagement and purchase intention in the specific SNS context, namely, Facebook, Instagram and Twitter. Design/methodology/approach The authors applied both exploratory and descriptive design based on a triangulation approach. The authors adapted an in-depth interview method in the first part to better specify our constructs and hypotheses. At the quantitative part, the authors conducted the survey method on 1,169 consumers as central part of the research for empirical testing and validating our conceptual model. The authors applied structural equation modeling analysis by using AMOS 22.0. Findings Overall, the results of this study indicate that social capital-based drivers have a significant role underlying the eWOM engagement of consumers, while engagement in eWOM has a further effect on their purchase intentions. In this study, social network culture appears as the most dominant social driver of consumers' engagement in eWOM, followed by tie strength and interpersonal trust. Research limitations/implications This study extends prior research on drivers of eWOM. An integrated conceptual model under SCT is proposed and tested to verify the dimensional interrelationships and effects on consumers' eWOM engagement and purchase intentions. Second, this work advances the understanding of eWOM behavior in a novel context, social networks. Cross-cultural comparison of our results in other regions of Turkey or different countries might enable generalizability, which is one of the limitations of the study. Practical implications This study highlights that consumers are incorporating recommendations into their social networking behavior. The findings of this study show that before constructing their social media strategies, marketers should first investigate the congruence between the cultural environment of the SNS in which they connect with their customers and the positioning of their products. Social implications This study suggests implications about privacy guidelines for SNS regulation setters. Policymakers should understand when and how consumers' profile and social tie information should be disclosed and accessed through their eWOM behaviors and try to develop trustful regulations. Originality/value This study serves as the first attempt to demonstrate that social capital drivers affect consumers' purchase intentions through their eWOM engagement by its robust conceptual model. No integrated model under SCT has ever been proposed and tested on consumers' eWOM engagement via SNSs.
  • Öğe
    Should luxury brands display their logos prominently? Implications for brand authenticity, coolness and behavioral intentions
    (Emerald Group Publishing Ltd, 2023) Shukla, Paurav; Cakici, N. Meltem; Khalifa, Dina
    PurposeExtant research captures the signaling and attitudinal effects of luxury brand prominence strategy; however, little is known about the underlying mechanisms that drive this effect. This study aims to uncover brand authenticity and brand coolness as parallel mediators driving the effects of brand prominence on luxury purchase intentions and explores the moderating role of consumers' self-brand connection.Design/methodology/approachThe research consisted of three experiments. Study 1 (n = 121) explored the direct effects of brand prominence among Chinese consumers. Using a sample of Turkish consumers (n = 115), Study 2, measured the mediation effects of brand authenticity and brand coolness. Study 3 (n = 211) examined how self-brand connection moderated the mediation effects among British customers.FindingsA luxury brand prominence strategy leads to negative perceptions of coolness and authenticity and, in turn, reduces purchase intentions. The negative effect of brand prominence is even more pronounced among consumers with high self-brand connection.Research limitations/implicationsThe study elaborates on how brand prominence informs consumers' perceptions of authenticity and coolness. In examining the role of self-brand connection, the study reveals a theoretically and managerially relevant boundary condition of this focal effect.Practical implicationsThe research highlights how luxury brands can use differing brand prominence strategies. This research informs brand managers on how to enhance brand authenticity and coolness while managing self-brand connection.Originality/valueThe study extends the luxury branding literature by explaining the brand prominence effect through the parallel mediators of brand authenticity and brand coolness. In contrast to extant research, the findings show that the negative effect of brand prominence is particularly strong among consumers with high self-brand connection.
  • Öğe
    Securing the embeddedness of psychosocial diffusion indicators into the Turkish construction industry Silence is no longer golden
    (Emerald Group Publishing Ltd, 2018) Goulding, Jack Steven; Ezcan, Volkan; Sutrisna, Monty
    Purpose - The paper aims to investigate the employee-stakeholder engagement on business performance. A psychosocial approach was used to evaluate employees' perception and role engagement on organisational performance, cognisant of: strategy development; leadership; fiscal acuity; employees' skills, empowerment; supply chain relationships; external stakeholders and wider societal beneficiaries. Design/methodology/approach - This research is context-bound to the Turkish construction industry. Findings generated from literature established a set of evidenced-based priorities for further investigation. A case study approach was conducted with three large architecture, engineering and construction (AEC) organisations to define psychosocial diffusion indicators and priorities for future uptake. Findings - Initial findings on psychosocial diffusion indicators and their impact on business performance are presented through a psychosocial diffusion model. Three interconnected facets are proffered for future uptake: capability (responsiveness), capability (flexibility) and capability (competence). Research limitations/implications - Findings are exclusively bound to the sample frame in question. No attempt has been made to undertake detailed cross-analysis/correlation to support internal/external consistency, validity or reliability. Practical implications - Organisations are able to reflect on their core business strategy to appreciate how psychosocial diffusion can be operationalised. Social implications - This work impinges on social factors embedded within (and across) organisational boundaries, including the AEC supply chain. It also relates to employer/employee relationships, psychological functioning and employee well-being. Originality/value - Originality rests with the identification of construction-related psychosocial indicators. It contributes to the wider body of knowledge on embedding psychosocial indicators into organisational systems and processes, adding further insight into systems thinking and business transformation.
  • Öğe
    Energy-related CO2 emission forecast for Turkey and Europe and Eurasia A discrete grey model approach
    (Emerald Group Publishing Ltd, 2017) Ayvaz, Berk; Kusakci, Ali Osman; Temur, Gul T.
    Purpose - The global warming, caused by the anthropogenic greenhouse gases, has been one of the major worldwide issues over the last decades. Among them, carbon dioxide (CO2) is the most important one and is responsible for more than the two-third of the greenhouse effect. Currently, greenhouse gas emissions and CO2 emissions - the root cause of the global warming - in particular are being examined closely in the fields of science and they also have been put on the agenda of the political leaders. The purpose of this paper is to predict the energy-related CO2 emissions through using different discrete grey models (DGMs) in Turkey and total Europe and Eurasia region. Design/methodology/approach - The proposed DGMs will be applied to predict CO2 emissions in Turkey and total Europe and Eurasia region from 2015 to 2030 using data set between 1965 and 2014. In the first stage of the study, DGMs without rolling mechanism (RM) will be used. In the second stage, DGMs with RM are constructed where the length of the rolling horizons of the respected models is optimised. Findings - In the first stage, estimated values show that non-homogeneous DGM is the best method to predict Turkey's energy-related CO2 emissions whereas DGM is the best method to predict the energy-related CO2 emissions for total Europe and Eurasia region. According to the results in the second stage, NDGM with RM (k = 26) is the best method for Turkey while optimised DGM with RM (k = 4) delivers most reliable estimates for total Europe and Eurasia region. Originality/value - This study illustrates the effect of different DGM approaches on the estimation performance for the Turkish energy-related CO2 emission data.
  • Öğe
    An integrated solution for space shuttle launching ramp
    (Emerald Group Publishing Ltd, 2019) Yucenur, G. Nilay; Subasi, Anil Sezer
    Purpose The purpose of this study is to select the most appropriate city in Turkey for space shuttle launching ramp. Design/methodology/approach In the proposed approach, an integrated methodology is used. The SWARA method is used in the first phase of the solution for determining criteria's importance weights. Based on the criteria weights obtained by the SWARA method, the WASPAS method is used for selecting the best alternative. Findings Mugla is selected for the most suitable city for the first space shuttle launching pad according to determined criteria and proposed model. Research limitations/implications - Although there are 81 cities in Turkey, 4 alternatives were selected for evaluation. It is possible to eliminate this limitation by the future studies with the implementation of proposed model to entire of Turkey. Practical implications - This proposed model can be used by the countries which want to have a new or first space shuttle launching ramp in the world. Originality/value Although some climatic conditions are pointed out on the location of the space shuttle launching ramp, in literature, there is not a comprehensive and detailed evaluation example as much as the model proposed in this study. Therefore, this study is the first in terms of the proposed model and applied techniques in the sectoral sense. In addition, the study is also a guide for solving the original model which is revealed in the selection of the most suitable alternative city for space shuttle launching ramp by different multi-criteria decision-making methods.
  • Öğe
    Effective international expansion strategies of emerging countries: the strategies that helped Arcelik
    (Emerald Group Publishing Ltd, 2013) Gulsoy, Tanses; Ozkanli, Ozlem; Lynch, Richard
    Purpose - This paper aims to present the case study of Arcelik, which has become Turkey's leading manufacturer and exporter of home appliances, as a means of offering insight into why, how and with what results companies from developing countries expand internationally. Design/methodology/approach - Primary data have been drawn from in-depth interviews conducted with senior executives and industry experts, and this has been based on a statistical analysis of the export and international strategies of Turkish home appliance and television set industry. Findings - The evidence indicates that international expansion may buffer a firm against fluctuations of demand in its home market and provide opportunities for growth. Difficulties faced by a later arrival from a developing country are greater than established rivals, and a developing country firm will have to rely on different resources and different operational strategies in developed vs developing markets. Research limitations/implications - Even though one case cannot yield general conclusions, it may indicate fruitful theoretical directions. This study raises issues worthy of further investigation. On the outset, it would be useful to apply the four propositions to more Turkish MNEs in order to test the robustness of the conclusions. Practical implications - The study has important implications for companies from developing countries. First, international expansion appears to be a viable means of offsetting home-market volatility for emerging-country firms. Second, international expansion is still predicated on significant investments in firm-specific advantages and their development may shorten the internationalization process. Originality/value - The report contributes to knowledge in the area of international expansion of companies from developing countries by providing evidence on how one company has achieved a world position in a highly competitive market through selective use of quality, innovation, and branding based on the competitive position that is available in each of its chosen markets. In particular, it contributes to the limited evidence on the international expansion of Turkish companies at the present time.
  • Öğe
    Internationalization of small firms: A case study of Turkish small- and medium-sized enterprises
    (Emerald Group Publishing Ltd, 2007) Karadeniz, E. Esra; Gocer, Kenan
    Purpose - The purpose of this paper is to investigate the factors that underlie the internationalization of small-medium-sized enterprises (SMEs) and to identify the most significant factors/variables that are related to the internationalization process of these firms in Turkey. Design/methodology/approach - The data for the analysis conducted in this study were collected from 471 owners/managers of SMEs in Turkey. This study examined the relationship of all variables in the internationalization of the small firms through use of Pearson and regression analysis. Findings - This study showed that the ability to be an exporter was related to the business age and size, the intensity of R&D, the growth rate of the domestic markets and the planning for export, pursued by SMEs. Research limitations/implications - The cross-sectional nature of this study may have limitations in regards to observing the direction and causality of some of the variables. The caution should be also taken when generalizing the findings beyond the scope of this study. The findings are limited to Turkish SMEs. Originality/value - A model in this study combines three classes of variables - firm, environmental, and management. Most empirical research has been concentrated on investigating one of these variables in relation to international performance. Earlier empirical research also concentrates on established larger firms and has not taken small firms into account. This study fills in a gap in the empirical research in terms of combining these variables to explain the internationalization process and studying the effect of these variables on smaller firms.
  • Öğe
    PIL simulations of an FWUAV under windy conditions
    (Emerald Group Publishing Ltd, 2018) Ulker, Hakan; Baykara, Cemal; Ozsoy, Can
    Purpose A fixed wing unmanned aerial vehicle (FWUAV) is targeted to perform processor in the loop (PIL) simulations for the flight scenarios such as straight and level, level climb, level turn, climbing turn and level steady heading sideslip under windy conditions such as steady wind (SW) and wind gust (WG) in a desired and controlled manner. Design/methodology/approach The constrained multi-input-multi-output (MIMO) lateral and longitudinal linear models-based model predictive controllers (MPCs) which are proposed in a previous study (Ulker et al., 2017) are tested in the PIL simulations under specified windy conditions. BeagleBone Black Rev C is used as a target hardware or processor in the PIL simulations. Findings The results of the PIL simulations show that the MPCs proposed in the previous study can achieve satisfactory performance and flying qualities for the all flight scenarios handled in this paper under windy conditions. Practical implications The MPCs proposed in the previous study can be easily implemented in the real world to a low-cost and small-sized board like BeagleBone Black Rev C which is used in this paper. Originality/value The proposed MPCs in the previous study which are capable of providing more flexibility in terms of tracking complex trajectories are showed to be able to be implemented to real system by means of PIL simulations under the changeable windy conditions which are difficult for performance tests.
  • Öğe
    Design of MPCs for a fixed wing UAV
    (Emerald Group Publishing Ltd, 2017) Ulker, Hakan; Baykara, Cemal; Ozsoy, Can
    Purpose - The purpose of the paper is to examine a fixed wing unmanned aerial vehicle (UAV) as it undergoes five flight scenarios under straight and level, level climb, level turn, climbing turn and level steady heading sideslip conditions in a desired and controlled manner using constrained multi input multi output (MIMO) model predictive controllers (MPCs). Design/methodology/approach - An MPC strategy based on the lateral and longitudinal linear models is proposed for the flight control design. Simulations are carried out for the nonlinear closed-loop aircraft Simulink model available from the University of Minnesota UAV research group with the implemented MIMO MPCs designed in this paper. Findings - The results of the simulations show that the MIMO MPCs can achieve satisfactory performance and flying qualities under three different test conditions in terms of existing unmeasured outputs and unmeasured output disturbances. Practical Implications - The MPCs designed in this paper can be implemented to UAVs. Therefore, the implementation is considered as an advanced research. Originality/value - The proposed MPC design in this paper provides more flexibility in terms of tracking complex trajectories comparing with the classical controllers in the literature. Besides they provide to change more than one reference of the states at any time.
  • Öğe
    Inventory inaccuracy and performance of collaborative supply chain practices
    (Emerald Group Publishing Limited, 2008) Sari, Kazim
    Purpose - This paper aims to explore the impact of inventory system inaccuracies on the benefits of collaborative supply chain practices under various supply chain scenarios. To achieve this purpose, two popular collaboration initiatives are considered in a four-stage supply chain. The first practice is a vendor managed inventory program where the distributor takes the full responsibility of managing the retailer's inventory. The second practice is a collaborative planning, forecasting, and replenishment program where all members work together to plan, forecast, and replenish the product. Design/methodology/approach - The study utilizes Monte Carlo computer simulation in an experimental design. Findings - The analysis suggests that while the inaccurate inventory records result in significant performance reductions for all supply chain configurations, their impact is substantially greater for the supply chains where members collaborate more closely on key supply chain management activities. In addition, the author also realize that the adverse impact of inaccurate inventory information is stronger under the conditions where lead times are shorter and/or where demand uncertainty in market place is lower. Practical implications - This analysis provides a means for practitioners to realize the importance of inventory accuracy to successful adaptation of collaborative supply chain practices. Moreover, this research also helps in understanding the supply chain conditions where the attempts of eliminating or reducing errors in inventory information are more crucial and more beneficial. Originality/value - Although there is a range of research focusing on collaborative practices, none of these studies considered the errors in inventory information. This is the first study to investigate the impact of inaccurate inventory information on the benefits of collaborative practices.
  • Öğe
    Hovering stability of a model helicopter
    (Emerald Group Publishing Ltd, 2016) Koc, Ilker Murat; Franko, Semuel; Ozsoy, Can
    Purpose - The purpose of this paper is to investigate the stability of a small scale six-degree-of-freedom nonlinear helicopter model at translator velocities and angular displacements while it is transiting to hover with different initial conditions. Design/methodology/approach - In this study, model predictive controller and linear quadratic regulator are designed and compared within each other for the stabilization of the open loop unstable nonlinear helicopter model. Findings - This study shows that the helicopter is able to reach to the desired target with good robustness, low control effort and small steady-state error under disturbances such as parameter uncertainties, mistuned controller. Originality/value - The purpose of using model predictive control for three axes of the autopilot is to decrease the control effort and to make the close-loop system insensitive against modeling uncertainties.
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    Selection of RFID solution provider A fuzzy multi-criteria decision model with Monte Carlo simulation
    (Emerald Group Publishing Limited, 2013) Sari, Kazim
    Purpose - The purpose of this paper is to provide a comprehensive framework to help managers of a business enterprise effectively evaluate candidate RFID solution providers and then select the most suitable one. Design/methodology/approach - The selection of an RFID solution provider is modeled as a new hybrid fuzzy multi-criteria decision making problem. The proposed decision model is based on integration of Monte Carlo simulation with fuzzy analytic hierarchy process (AHP) and fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods. In addition, an illustrative case is used to exemplify the proposed approach. Findings - A quantitative methodology based on a structured framework, for the selection of the most appropriate RFID solution provider. Practical implications - This research study is a very useful source of information for managers of a business enterprise in making decisions about evaluation and selection of RFID solution providers or RFID system integrators. Originality/value - This study addresses the evaluation and selection of RFID solution providers for the managers of a business enterprise and proposes a new hybrid decision-making methodology for the problem.
  • Öğe
    The microbiological quality of stuffed mussels (Midye Dolma) sold in Istanbul
    (Emerald Group Publishing Limited, 2008) Bingol, Enver Baris; Colak, Hilal; Hampikyan, Hamparsun; Muratoglu, Karlo
    Purpose - This study was performed to determine the microbial quality of stuffed mussels and to discuss the microbiological quality criteria of ready-to-eat (RTE) foods defined in the Turkish Food Codex (TFC). Design/methodology/approach - Stuffed mussel (Midye Dolma), which can be classified as RTE foods, made from mussel and rice, cooked separately then put together in the shell, is commonly consumed in Turkey. This special food might be an important source of microorganisms especially pathogen bacteria because of preparation and serving process. During the period of March-October 2006, a total of 168 stuffed mussel samples were collected randomly from restaurants, buffets and street sellers located in Istanbul and analysed some microbiological parameters. Findings - Coliforms were detected in 130 (77.38 per cent), Eschetichia coli in 37 (22.02 per cent), Staphylococcus aureus in 40 (23.80 per cent), Bacillus cereus in 65 (38.69 per cent), yeast and moulds in 147 (87.50 per cent) and sulphite-reducing anaerob bacteria in 61 (36.30 per cent) stuffed mussel samples, respectively. Total aerobic bacteria count (TAB) was between 1.0 X 10(2) and 3.2 X 10(7) CFU/g. No Salmonella spp. was detected in analysed samples. Originality/value - This is the first comprehensive study to provide information on the microbiological quality of stuffed mussels sold in Istanbul, Turkey. This information is important in the determination of measures that can be taken to control the safety of these cooked or prepared foods.