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Article
Publication date: 5 September 2008

Emre Kiyak, Ömer Çetin and Ayşe Kahvecioğlu

The purpose of this paper is to generate residuals which can be used to detect fault and isolate on a vertical takeoff and landing (VTOL) aircraft dynamic model.

Abstract

Purpose

The purpose of this paper is to generate residuals which can be used to detect fault and isolate on a vertical takeoff and landing (VTOL) aircraft dynamic model.

Design/methodology/approach

In the proposed approach, a generalized observer scheme method based on an unknown input observer is used for residual generation and applied to detect and isolate a faulty sensor. A bank of robust unknown input observers estimates the state variables of the system and gathers necessary information for fault detection and isolation purposes.

Findings

A sinus signal is considered as a non‐linear disturbance in simulations. A failure simulation was prepared in different times. In this situation an unknown input observer should be designed which could predict the states of the system against the disturbances or unknown inputs. In the real world, there exist unknown inputs such as system non‐linearities, noise and disturbances. The paper shows that the system based on UIO is robust for unknown inputs mentioned above.

Originality/value

It is simulated on a VTOL dynamic model using MATLAB/Simulink. Any single sensor fault could be detected and isolated correctly. This kind of observer is also robust and flexible.

Details

Aircraft Engineering and Aerospace Technology, vol. 80 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 6 September 2011

Enver Baris Bingol, Omer Cetin and Karlo Muratoglu

The purpose of this study is to investigate the effect of lemon juice on the survival of Salmonella Enteritidis and Escherichia coli in cig kofte (raw meatball).

Abstract

Purpose

The purpose of this study is to investigate the effect of lemon juice on the survival of Salmonella Enteritidis and Escherichia coli in cig kofte (raw meatball).

Design/methodology/approach

Cig kofte samples were inoculated one by one with both bacteria at high inoculum levels and were treated with different doses of fresh lemon juice (2, 5, 10 and 15 ml) for 10 seconds, 30 seconds, and 1, 5, 15, 30 and 60 minutes.

Findings

Treatments of lemon juice for different exposure times caused reduction ranging between 0.1 and 1.7 log CFU/g for Salmonella Enteritidis and 0.1 and 2.1 log CFU/g for E.coli. Results showed that lemon juice caused slight decrease in Salmonella Enteritidis and E.coli as an immediate inhibitor, but this effect increased with concentration and time.

Originality/value

This is a research study to provide information on the effectiveness of lemon juice which is squeezed generally before eating cig kofte, on the presence of the surface flora to strengthen the hygienic quality of the product. Inactivation effect of lemon juice on Salmonella Enteritidis and E.coli may give a practical and easy way of providing food safety for cig kofte.

Details

British Food Journal, vol. 113 no. 9
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 1 February 1994

A.Z. Keller, Çetin Dogan and Ömer Eroglu

Explores whether the current implementation of privatization inTurkey is consistent with original privatization objectives as laid downin the original government plan…

1421

Abstract

Explores whether the current implementation of privatization in Turkey is consistent with original privatization objectives as laid down in the original government plan. Presents analysis of hard data obtained from the Public Participation Fund, the agency responsible for the planning and execution of the programme and entrusted with selling the state′s shares in companies, and the results of certain questions from a survey undertaken in Turkey to assess the opinions of senior managers, drawn from both the state and private sector, and academics, regarding the implementation of the privatization policy. Finds that, to date, implementation of the privatization programme is contrary to the original objectives of the Turkish government.

Details

International Journal of Public Sector Management, vol. 7 no. 1
Type: Research Article
ISSN: 0951-3558

Keywords

Article
Publication date: 31 October 2018

Murat Güler and Fatih Çetin

The purpose of this study is to investigate the relationship between personal resources and subjective well-being by focusing on the moderation role of resource…

2641

Abstract

Purpose

The purpose of this study is to investigate the relationship between personal resources and subjective well-being by focusing on the moderation role of resource threatening and consuming conditions on this relationship.

Design/methodology/approach

The quantitative research data were collected from a sample of 465 lawyers working in Turkey by using a self-report questionnaire form. The confirmatory factor analysis, correlation and regression analyses were performed to test the research hypothesis.

Findings

The results showed that personal resources influence positively subjective well-being with the three-way interactions (moderated moderation) of surface acting and perceived stress. The interactions between variables were significant at the conditions of the high level of surface acting and the low level of stress.

Originality/value

The current research contributes to our understanding of how personal resources can be consumed in such a way that individual well-being is enhanced. The findings also raise a new question about whether or not surface acting causes negative consequences in all conditions.

Article
Publication date: 15 March 2018

Fatih Çetin and Duysal Aşkun

Today, organizations work hard to improve the motivation of their employees and related knowledge, skills and abilities to enhance work performance. Among many other…

4685

Abstract

Purpose

Today, organizations work hard to improve the motivation of their employees and related knowledge, skills and abilities to enhance work performance. Among many other variables, self-efficacy proved to have an influential role in work performance. The main purpose of the current study is to investigate the role of occupational self-efficacy on work performance through intrinsic motivation by using a longitudinal analysis.

Design/methodology/approach

Participants were 76 employees from diverse organizations operating in an organized industrial region in Turkey. Participants filled in a weekly questionnaire during ten consecutive weeks.

Findings

Results of multilevel analyses confirmed our hypotheses by showing that occupational self-efficacy and intrinsic motivation have a significant influential role over work performance, and intrinsic motivation serve as a partial mediator in this relationship.

Originality/value

The study findings also reveal important information for organizational and managerial practices to improve employee motivation and performance.

Article
Publication date: 8 January 2018

Ipek Kalemci Tüzün, Fatih Çetin and H. Nejat Basim

The purpose of this paper is to increase understanding of the link between various identification foci and performance, and to test whether one’s psychological capital…

1720

Abstract

Purpose

The purpose of this paper is to increase understanding of the link between various identification foci and performance, and to test whether one’s psychological capital (PsyCap) can explain the influence of collective or relational identification on job performance.

Design/methodology/approach

The study sample comprised 235 academicians working in a foundation university from Turkey. The questionnaires were practiced in two different time intervals with using an identifier coding system for avoiding common method bias issues. The authors used structural equation modeling with using AMOS v23.0.

Findings

The results showed that PsyCap has positive effects on the job performance and work group identification flourishes employees PsyCap level; there is no evidence of any mediating effect of PsyCap on the relationships between various organizational identification foci and job performance.

Originality/value

This study extends previous research by providing evidence of that rather than the other identification target (organization, work unit, and career) identification with supervisor influenced on job performance.

Details

International Journal of Productivity and Performance Management, vol. 67 no. 1
Type: Research Article
ISSN: 1741-0401

Keywords

Book part
Publication date: 13 May 2021

Omer Sarac

In today's globalising conditions, tourism is marketed as a combined product because the demand for tourism increases as the product differs. It is very difficult for…

Abstract

In today's globalising conditions, tourism is marketed as a combined product because the demand for tourism increases as the product differs. It is very difficult for tourism destinations, which emerge as a result of the combination of attractiveness, accessibility, tourism businesses, activity and image elements, to survive because tourism destination stakeholders have different goals and objectives. Therefore, there is a need for an effective destination management in which management functions (planning, organising, coordination, commanding (leading) and control) will be employed. Together with the destination management, stakeholders with different goals and objectives are expected to operate in line with a common goal. The clustering of tourism businesses, one of the stakeholders of the tourism destination, plays a very important role in the emergence of destination management. In addition, this situation causes businesses to act not only in line with their own interests but also in the interests of the destination. While avoiding activities that would endanger the existence of the destination with the unions they establish, they cause local administrations and fund managers to act in line with the infrastructure, superstructure and development opportunities needed. In addition to this, while ensuring the use and protection of social capital in that region, it also enables the development of intellectual capital. On the other hand, it causes the opening of new main and auxiliary enterprises and plays an active role in increasing the welfare level of the region. Therefore, clustering is very important in successful destination management.

Details

Overtourism as Destination Risk
Type: Book
ISBN: 978-1-83909-707-2

Keywords

Article
Publication date: 5 September 2022

Ömer Saraç, Vahit Oğuz Kiper and Orhan Batman

Hedonic behavior is a well-known phenomenon for tourism activities by the nature of tourism itself. However, there is a possible conflict between the structure of halal…

Abstract

Purpose

Hedonic behavior is a well-known phenomenon for tourism activities by the nature of tourism itself. However, there is a possible conflict between the structure of halal tourism and hedonic behavior. This paper aims to investigate the hedonic perception levels of halal-sensitive tourists (HSTs) while questioning their travel motivations.

Design/methodology/approach

According to the aim of this study, quantitative approach has been adopted via data gathering within World Halal Summit. A total of 1,123 surveys were gathered face to face from participants. Factor analysis applied to confirm validity of the data set while also running Cronbach alpha test through all dimensions. Also, frequency and mean analyses were applied in addition to t-test for comparing tests.

Findings

Results briefly show that HSTs have an average level of perception of hedonism. They also travel once or twice a year for religious, social or environmental reasons which supports the finding about their hedonism perception.

Research limitations/implications

The research is also important in the applied field, especially in terms of decision-makers and supply determinants in destination management. Because if it is determined that the HSTs exhibit a utilitarian consumption, it has a guiding feature for the decision-makers to prefer halal tourism in terms of environmental management in the destination. In terms of the economic sustainability of the research destination or businesses, it also serves as a guide for the supply determinants in their investment activities.

Originality/value

This research is considerably important in terms of putting the HST typology on a conceptual basis in the theoretical field. In the research, it is tested whether the HSTs are hedonic consumers; in other words, whether they comply with the Islamic religious prohibitions. The tendency of HSTs to comply with the prohibitions reveals that they are utilitarian consumers, while halal tourism is a responsible tourism that cares about sustainability.

Details

Journal of Islamic Marketing, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0833

Keywords

Article
Publication date: 30 September 2020

Gökhan Sur and Ömer Erkan

Drilling of carbon fiber reinforced plastic (CFRP) composite plates with high surface quality are of great importance for assembly operations. The article aims to optimize…

Abstract

Purpose

Drilling of carbon fiber reinforced plastic (CFRP) composite plates with high surface quality are of great importance for assembly operations. The article aims to optimize the drill geometry and cutting parameters to improve the surface quality of CFRP composite material. In this study, CFRP plates were drilled with uncoated carbide drill bits with standard and step geometry. Thus, the effects of standard and step drill bits on surface quality have been examined comparatively. In addition, optimum output parameters were determined by Taguchi, ANOVA and multiple decision-making methods.

Design/methodology/approach

Drill bit point angles were selected as 90°, 110° and 130°. In cutting parameters, three different cutting speeds (25, 50 and 75 m/min) and three different feeds (0.1, 0.15 and 0.2 mm/rev) were determined. L18 orthogonal sequence was used with Taguchi experimental design. Three important output parameters affecting the surface quality are determined as thrust force, surface roughness and delamination factor. For each output parameter, the effects of drill geometry and cutting parameters were evaluated. Input parameters affecting output parameters were analyzed using the ANOVA method. Output parameters were estimated by creating regression equations. Weights were determined using the analytic hierarchy process (AHP) method, and multiple output parameters were optimized using technique for order preference by Similarity to An ideal solution (TOPSIS).

Findings

It has been determined from the experimental results that step drills generate smaller thrust forces than standard drills. However, it has been determined that it creates greater surface roughness and delamination factor. From the Taguchi analysis, the optimum input parameters for Fz step tool geometry, 90° point angle, 75 m/min cutting speed and 0.1 mm/rev feed. For Fd, are standard tool geometry, 90° point angle, 25 m/min cutting speed and 0.1 mm/rev feed and for Ra, are standard tool geometry, 130° point angle, 25 m/min cutting speed and 0.1 mm/rev feed. ANOVA analysis determined that the most important parameter on Fd is the tip angle, with 56.33%. The most important parameter on Ra and Fz was found to be 40.53% and 77.06% tool geometry, respectively. As a result of the optimization with multiple criteria decision-making methods, the test order that gave the best surface quality was found as 4–1-9–5-8–17-2–13-6–16-18–15-11–10-3–12-14. The results of the test number 4, which gives the best surface quality, namely, the thrust force is 91.86 N, the surface roughness is 0.75 µm and the delamination factor is 1.043. As a result of experiment number 14, which gave the worst surface quality, the thrust force was 149.88 N, the surface roughness was 3.03 µm and the delamination factor was 1.163.

Practical implications

Surface quality is an essential parameter in the drilling of CFRP plates. Cutting tool geometry comes first among the parameters affecting this. Therefore, different cutting tool geometries are preferred. A comparison of these cutting tools is discussed in detail. On the other hand, thrust force, delamination factor and surface roughness, which are the output parameters that determine the surface quality, have been optimized using the TOPSIS and AHP method. In this way, this situation, which seems complicated, is presented in a plain and understandable form.

Originality/value

In the experiments, cutting tools with different geometries are included. Comparatively, its effects on surface quality were examined. The hole damage mechanism affecting the surface quality is discussed in detail. The results were optimized by evaluating Taguchi, ANOVA, TOPSIS and AHP methods together.

Details

Engineering Computations, vol. 38 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Book part
Publication date: 16 June 2021

Hiroko Kawamorita, Yashar Salamzadeh, Ali Kahramanoğlu, Kürşat Demiryürek, Nur İlkay Abacı and Noriyuki Takahashi

This chapter addresses the impact of gendered social capital in developing countries to understand the barriers and opportunities to women's entrepreneurship with social…

Abstract

This chapter addresses the impact of gendered social capital in developing countries to understand the barriers and opportunities to women's entrepreneurship with social capital development and also to examine factors influencing the development of social capital for women and how the identified factors benefit the creation of their entrepreneurial activities. This study follows a systemic literature review to achieve the purpose of the research by examining the selected articles in both English and Turkish, followed by factor comparison between developing, developed countries, and world datasets obtained from Global Entrepreneurship Monitor (GEM) database. The finding shows that social capital strongly impacts the entrepreneurial activities among women entrepreneurs in developing countries, especially in Turkey. Although the academic and practical studies on this field were started about two decades ago in Turkey, it has faced a radical increase in last 5 years and many practitioners and scholars working on these concepts. The clusters in English and Turkish resources are almost the same; however, the density and number of key terms are much lower in Turkish literature which shows a gap for Turkish researchers to publish more in this field to examine variables for better view about women entrepreneurship and social capital related to it.

Details

The Emerald Handbook of Women and Entrepreneurship in Developing Economies
Type: Book
ISBN: 978-1-80071-327-7

Keywords

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