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  • Öge
    Green supply chain management practices' effect on the sustainability performance: A case study in the Turkish shipyards
    (Graduate School, 2023-05-23) Tantan, Mehmet ; Akdağ Camgöz, Hatice ; 507002103 ; Management Engineering
    The study in this Ph.D.thesis concerns the green supply chain management practices, their impacts on sustainability performance; environmental, economic, and social performance by conducting a case study in Turkish shipyards. The more detailed objectives are; to select the optimum green supply chain management practices to fit in shipyards, to examine the impact of green supply chain management practices on the sustainability performance of shipyards, the moderator effect of environmental uncertainty on the relationship between green supply chain and sustainability performance, the mediator effect of environmental uncertainty between green supply chain and sustainability performance and the determine the penetration level of green supply chain management practices on the Turkish shipyards. Sustainability is an essential issue in the twenty-first century regarding the environmental consequences of climate change. Green supply chain management progressively emerged to improve environmental performance. Although environmental, sustainability, green supply chain areas are popular study subjects, shipbuilding and shipyards were not examined in detail. A systematic literature review between 1980 and 2020 unveiled rare studies concerning green supply chain management sustainability in shipyards and shipbuilding. The filtered articles were categorized into shipbreaking, shipbuilding, maritime, and various. China and South Korea emerged as leading areas for research in Asia since shipbuilding is seen as a driving factor for development and growth in those economies. In Europe, Spain, Turkey, and Holland emerged as research areas. The main focus areas in the shipbuilding category are shipyard layout design according to the greenfield project, sustainable growth directions for small and medium shipyards, the ways to improve the sustainability in the shipbuilding supply chain, green shipping, and green manufacturing in the shipyard. Therefore, this thesis is the first study of the impact of green supply chain management practices on shipyards' sustainability performance. Green supply chain management is challenging to describe because of the broad concept. Many academicians reached different definitions. An increasing number of studies about the relationship between Green supply chain management practices and companies' performance have existed in the literature since 2014. These studies have categorized sustainability performance as environmental, economic, social, and operational performance. In contrast, various GSCM practices such as green purchasing, green packaging, recycling, eco-design, internal environmental management, reverse logistic, green production, green marketing, environmental collaboration with suppliers and customers have been questioned in these studies. The researchers found both negative and positive, primarily partial, relationships between GSCM practices and the company's performances. The authors reviewed all practices in the literature and considered practices directly related to the shipbuilding industry. For example, environmental training is a part of internal environmental management, and therefore these two applications converged as environmental management. Practices like green packaging and green transportation have little effect on the shipbuilding process and are omitted from the study. Consequently, green design, green purchasing, green production, green marketing, environmental management, recycling are selected as exogenous latent variables for the research model. Economic, environmental, and social performances are entered as endogenous latent variables for the research model. The environmental uncertainty (ENVR-UNCER) is embedded in the research model as either a moderator or a mediator variable. Environmental uncertainty is measured as demand, supply, and technology uncertainty. The shipbuilding industry creates substantial economic value but causes many environmental and social issues. Sustainability, environmentally driven regulations, and voluntary standards adopted in the sector have impacted shipbuilding and shipyards in the case of new design and construction standards. Major international shipbuilding companies publish yearly sustainability reports indicating sustainable development goal achievements. The survey is based on academic studies in Turkish chemical, electronical, automotive, food packaging industries. The survey consists of three main parts. The first part contains an introduction letter with a brief explanation of the study. The second part is the demographic questions like general information about the company and the quality and environmental certificates. In the third part, the survey questions are grouped to green supply chain management practices, environmental uncertainty, and sustainable performance. The understanding of scales by the applicant and time constraints were two main obstacles to accomplishing the survey completion rate. Therefore, the author summarized the scales into expressed sentences and limited them to 33 questions. The survey filling time is a critical factor. It is arranged for around 15 minutes on average because most executives claim the intense work environment and use it as an excuse not to fill the survey. The survey used a 5-Likert type, the most preferred scale in the literature. A pilot test with shipyard executives and shipyards' owners enabled improved scales and corrected the expression failures. The final survey is applied among the GISBIR members by email. The responses are stored in the VETI system and downloaded for analysis. A favorable finding of the survey is the certification outcome. All shipyards have a minimum of two certificates (ISO 9001 and ISO 14001, 30% of the answers). Only two small shipyards have a single certification, ISO 9001. A high portion of the shipyards has all three certificates (ISO 9001, ISO 14001, and ISO 45001). Those findings proved that Turkish shipyards embraced environmental issues and took necessary internal and external actions to improve their business competence. Since the Turkish shipyard quantities are limited to 68, partial least square structural equation modeling (PLS-SEM) is selected to eliminate the sample size constraint. The research model is defined in the SmartPLS software. To decrease the number of relationships and make the model more parsimonious and simple, authors preferred to form a hierarchical-order model, ease the calculation and simplify the research model. The disjoint two-stage approach is implemented. Green design, green purchasing, green production, green marketing, environmental management, and recycling formed the higher-order construct named GSCM. Demand uncertainty, technology uncertainty, and supply uncertainty formed the higher-order construct named ENVR-UNCER. Demand uncertainty indicator is omitted to obtain HOC reliability convergent and discriminant validity during the assessment of the measurement model. All other indicators satisfied the criteria and were kept in the model. After the structural model assessment, GSCM practices have been found to impact positively on economic and social performance, but not environmental performance. The environmental uncertainty did not have a moderating effect but mediates only the relationship between GSCM practices and social performance.
  • Öge
    İş modeli yeniliğinin işletme performansı üzerine etkileri: Örgüt içi ve örgüt dışı faktörlerin rolü
    (Lisansüstü Eğitim Enstitüsü, 2023-04-06) Dayıoğlu, Mustafa ; Akdoğan Küskü, Fatma ; 507062004 ; İşletme Mühendisliği
    Bu çalışma ilgili akademik yazına dört önemli katkı sunmakatadır. Katkılardan ilki iş modeli yeniliği kavramı ile ilgilidir. Farklı disiplinlerce ele alındığından iş modeli yeniliği kavramının tanımlanmasında ve dolayısı ile ölçümlenmesinde zorluklar bulunmaktadır. Bu çalışmada, sektör ve işletme büyüklüğünden bağımsız olacak şekilde heterojen ortamlar göz önüne alınarak yeni bir iş modeli yeniliği ölçeği geliştirilmiştir. İkinci katkı, iş modeli yeniliğinin gerçekleştirilmesini sağlayan örgüt içi unsur olan stratejik çeviklik kavramı ile ilgilidir. Farklı iş kollarının yer aldığı heterojen bağlamlar için doğruluğu ve geçerliliği test edilmiş bir stratejik çeviklik ölçeği geliştirilmiştir. Esasında, iş modeli yeniliği ve stratejik çeviklik için literatürde artık yeni ölçekler geliştirilmediği, mevcut ölçekler üzerinden araştırmalar yapıldığı gözlenmektedir. Ancak mevcut ölçekler sermaye yoğun işletmelerin yer aldığı ülkelerde yapılan araştırmalar ile gerçekleştirilmiştir. Oysa bu tez çalışmasında hem emek yoğun hem de sermaye yoğun işletmeler örnekleme dahil olduğu için ölçek geliştirme açısından ilgili yazına önemli katkılar sunulabilecektir. Üçüncü katkı, stratejik çeviklik ve alt bileşenleri ile iş modeli yeniliği arasındaki anlamlı ilişkinin, ayrıca iş modeli yeniliğinin işletme performansı üzerinde olumlu etkisinin ampirik olarak doğrulamasının yapılmasıdır. Dördüncü önemli katkı ise, iş modeli yeniliğini etkinleştiren ulusal ve küresel çevre faktörlerinin, iş modeli yeniliği ve işletme performansı arasındaki ilişkide düzenleyici (güçlendirici) (moderating) ve aracılık (tetikleyici) (mediating) etkilerinin ampirik olarak test edilmesidir. Hatta son yıllarda çevresel değişimlerin getirdiği müşteri taleplerindeki değişim ve yeni teknolojilerin getirdiği ürün/hizmet fırsatlardan dolayı çevresel değişimlerin işletmeleri yeniliğe yönlendirmesi ve bu sayede de işletmelerin performanslarını olumlu yönde etkilemesi ile ilgili hipotezleri kanıtlayan çalışmalar da yapılmaya başlamıştır. Fakat bu çalışmalar işletmelerin değer kurgularının güncellenmesinden ziyade hizmet ve ürün yeniliği ile sınırlı kalmaktadır. Bu çalışmada ise, oluşturulan araştırma modelleri ile, ulusal ve küresel çevre faktörlerinin iş modeli yeniliğini gerçekleştiren faktörlerle ilişkisi hem aracılık (tetikleyici) hem de düzenleyicilik ilişkisi olarak ele alınmakta, böylece akademik yazına önemli ampirik katkılar sunulmaktadır.
  • Öge
    Designing business model framework for public bus transportation authorities: A fuzzy approach
    (Graduate School, 2023-02-22) Buran, Büşra ; Erçek, Mehmet ; 507162010 ; Management Engineering
    Covid-19, which has taken the world under its influence, has also deeply affected the public transportation sector. While public transportation is sustainable with subsidies, the gap between expenses and incomes has grown with the effect of Covid-19. The sector, which meets the majority of its revenues from tickets, decreased by ninety percent during the days of curfews during the pandemic period. Expenses such as disinfection, mask, etc. increased with the addition of additional items. Despite all the difficulties, public transportation continued to serve without stopping during the pandemic period. For this reason, public transportation is seen as a backbone for the cities. Especially in developed and developing countries, it plays a critical role to overcome traffic jams. To achieve this, the service quality of public transportation is seen as a key point. The service quality of public transportation depends on different factors such as operation, repair and maintenance, audit, and management. From the management side, the business model provides a holistic perspective due to taking into account activity, value, and financial status. Business models represent a critical tool for strategic management. It provides managers with an integrated perspective to shape business operations regarding the activity, value, and finance dimensions. When activity composes of key partners, key resources, and key activities, value includes value proposition, customer segments, channels, and customer relationships. Lastly, the finance block comprises revenue streams and costs from Business Model Canvas (BMC) perspective. It serves to understand, communicate, share, change, measure, simulate, and learn more about the different aspects of the firms. According to the type of organization, the business model can be varied such as profit-based or social-based. This thesis presents a business model canvas framework for public transportation organizations including impact factors and their external environment. Impact factor includes social and environmental issues for public bus transportation such as elderly people, disabled people, electric buses, and green transportation. From an external view, PESTEL analysis is taken into account which is political, economical, social, technological, legal, and environmental. Taking into account impact factors and the external environment provides managers or policymakers with a holistic perspective to manage effectively. The main and sub-criteria of the model are designed according to the literature under three hierarchical levels. While the first level of the model is the main criteria which are internal and external environment criteria, the second level comprises sub-criteria of internal and external environment criteria which are business model canvas and PESTEL analysis. Finally, the third level is related to the sub-criteria of the business model and PESTEL analysis. In addition, this thesis aims to query the viability of a new strategic action tool specifically geared to the interests of public bus transportation authorities (PBTAs) around the globe and explore the degree of homogeneity in their responses as well as their possible drivers of them. To answer its research question, the study first offers a generic business model design for a PBTA, which integrates an extended version of the business model canvas with external environmental factors in order to enhance its sustainability. Subsequently, the importance attributions of international transportation experts to different model components are evaluated by using the Spherical and Intuitionistic Fuzzy AHP method. The proposed model is evaluated by experts from four continents: America, Asia, Australia, and Europe. International experts are selected according to their experience. They are selected from different departments which are planning, operation, innovation, strategy development, and finance with more than ten years of experience. There are different methods in the literature such as Multi-Attribute Utility Theory, Analytic Hierarchy Process (AHP), Analytic Network Process (ANP), Fuzzy Set Theory, Case-Based Reasoning, Data Envelopment Analysis, Simple Multi-Attribute Rating Technique, Goal Programming, Elimination and Choice Translating Reality (ELECTRE), Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE), Simple Additive Weighting, Multicriteria Optimization and Com promise Solution (VIseKriterijumska Optimizacija I Kompromisno Resenje-VIKOR), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), and The Weighted Aggregated Sum Product Assessment (WASPAS). Analytic Hierarchy Process (AHP) is mostly used method due to its ease of application, flexibility, applicable to many subjects. But in some circumstances such as vagueness, complexity fuzzy logic is preferred to classical AHP. In fuzzy logic, there are different fuzzy sets. Some of those are Ordinary, Interval-Valued, Intuitionistic, Neutrosophic, Nonstationary, Hesitant, and Spherical. In this problem, fuzzy logic is applied to the model with two extensions which are Intuitionistic Fuzzy Sets (IFS) and Spherical Fuzzy Sets (SFS) to evaluate the proposed model. A solution set is also provided with a traditional AHP in order to check the robustness of the former methods. According to the results, the internal environment is ranked as the most important criterion at the first level for all methods. Whereas the activity element is ranked first at the second level, key partners are ranked first at the third level for all methods. The relative similarity of the results obtained by the traditional and Intuitionistic Fuzzy AHP model suggests that the Spherical Fuzzy AHP model may have better potential to handle the vagueness of the business modeling problems. Sensitivity analyses show that the model is sensitive to expert judgments. From the convergence-divergence perspective, the expert opinions tend to converge more on the internal components of the model and diverge on the external components, especially regarding economic and technological factors. A strategic response action set is also designed to facilitate the adoption of the model by PBTAs. The strategic responses include short and long terms actions, separately. When unexpected conditions such as pandemics trigger short-run responses, the long-run term is mobilized by the planning process. Innovation of the business model is important as designing it. Changing political, economical, social, technological, and legal conditions, the business models can be needed to redesign to survive in the business ecosystem. Development of the proposed business model can be tracked using defined performance indicators time by time. This study contributes to the works of both academicians and practitioners in terms of designing and evaluating public transportation business models. The study not only extends the research on the strategic management of the public bus transportation domain but also contributes to the convergence and divergence debate by offering a reconciliatory duality perspective.
  • Öge
    Liquidity in emerging country bond markets: A comparison of bid-ask spread proxies and determinants of bid-ask spread
    (Graduate School, 2023-04-12) Su, Emre ; Tokmakçıoğlu, Kaya ; 507142003 ; Management Engineering
    Many of the emerging market countries have been issued large amounts of local currency bonds in order to finance their budget deficits. Therefore, the attention to the emerging country bonds increased and, different aspects of these assets are investigated in order to analyse market microstructures. Liquidity is one of the most important characteristics of the financial assets and markets. As liquidity affects asset returns, investment decisions and market characteristics, all of the market participants are attracted to measurement and forecast of a financial security's liquidity. So, liquidity measurement is essential to understand market dynamics. The bid-ask spread, which is the difference between the best bid and ask prices, represents the explicit trade costs, and is an important liquidity measure. In this thesis, we look for an efficient way to estimate the bid-ask spread for sovereign bonds, and analyze the bond-specific and country-specific determinants of the bid-ask spread in the emerging market countries. The performances' of the bid-ask spread measures are compared, and the bond-level characteristics' effects on the bid-ask are investigated. We implement empirical analysis on two distinct data sets. For the first data set, we analyze Turkish sovereign bonds traded in Borsa Istanbul Debt Securities Market. We build a relative quoted bid-ask spread as a benchmark using intraday quote data, and compare the forecast performances of the bid-ask spread measures. According to the regression results, the spread measures that use low-frequency data are able to represent and estimate spread dynamics, and Closing Percent Quoted Spread outperforms the other measures. Moreover, a panel data analysis is applied to investigate the bond specific features' effects on the bid-ask spread, and the regression analysis shows that bond liquidity is significantly affected by bond specific features. The shorter term to maturity or the greater trade volume, the narrower relative bid-ask spread. Further, bond type is significantly influential on the bid-ask spread. For the second data set, we analyze sovereign bonds from six emerging market countries. A panel regression model is implemented in order to examine the country-level and bond-level features' effects on the sovereign bond bid-ask spread and liquidity. According to our empirical analysis, issuer country credit risk, market return and bond yield are statistically significant determinants of the bid-ask spread for emerging country sovereign bonds.
  • Öge
    Disposition bias for different investor categories in Borsa Istanbul
    (Graduate School, 2022-10-18) Kahya, Evrim Hilal ; Ekinci, Cumhur Enis ; 507102007 ; Management Engineering
    Financial theory based many of its theoretical models on the rationality of investors which was challenged by behavioral finance since two decades. Disposition bias is among the many biases that investors face with and behaving against rationality assumption. Having its base from Tsversky and Kahneman (1979) prospect theory, in which the individuals are assumed to be loss averse, Shefrin and Statman (1985) named this loss aversion as "Disposition bias" for the behaviors of the investors, basically refer to the tendency to sell the investment held for a loss at a slower rate than the investment held for a gain. Related with our study, it is important to explain the human psychology on positive and negative outcomes. It is found that we approach positive occurrences differently from negative ones. One way or another we overweigh the positive circumstances and underweigh the negative ones and shape our daily choices based on this subjective evaluation. This discrepancy leads to irrational choices and behaviors which is the main issue in coping mechanisms of human beings. This irrational behavior finds its projection on finance through disposition bias. If an investor is exposed to disposition bias, she behaves differently when faced with loser portfolio compared to winner portfolio. The psychology of this two different choices was analyzed by Shefrin and Statman (1986) with prospect theory of Kahneman and Tversky (1979). This theory suggested that investors are risk takers when a loss is occurred and refrain from risk when a gain is certain. Weber and Camerer (1998), Anaert et al. (2008), and Lee et al. (2008) checked it through either experiments, simulations and other kinds of statistical analysis and found statistically significant results favoring the prospect theory, whereas Odean (1998), Jiao (2017), and Barberis and Xiong (2009) found mixed results in favoring this theory and many other such as Kaustica (2010), Hens and Vlcek (2011), Ben-David and Hirshleifer (2012), and Kubinska et al. (2012) found no statistically significant results favoring prospect theory. Other than prospect theory, the disposition bias was tried to be explained through mental accounting and regret aversion by Brown et al. (2006), Dhar and Zhu (2006), Kaustica (2010), Goo et al. (2010), and Rau (2015), Self-attribution Bias by Barber et al. (2007), Direct Causal Effect of Emotions by Summers and Duxbury (2012), Aspara and Hoffmann (2015), Garling et al. (2016), and Chang et al. (2016) but again the results from all these studies are mixed. The main results for the disposition bias analysis was that investors are mainly less willing to realize losses than gains. Disposition bias not only was analyzed with respect to general investor groups, it has been analyzed with many aspects from different investors types, different cultures, to the effects of the disposition bias on the stock prices, wealth of investors, and other behavioral biases. In studying disposition on different behaviors of investor groups, it was hypothesized that when one can find the difference among groups, then one can come up with a better explanatory idea on the reasoning behind the DB. Grindblatt and Keloharju (2001), Shu et al. (2005), Lehenkari and Perttunen (2005), Barbet et al. (2007)., Chen et al. (2007), Boolell-Gunesh (2009), Goo et al. (2010), and Frino et al. (2014) and many others analyzed the effect of gender and/or age on DB, Shapira and Venezia (2001), Shu et al. (2005), Lehenkari and Perttunen (2004) Dhar and Zhu (2006), Weber and Welfens (2008), Boolell-Gunesh (2009), Choe and Eom (2010), and others analyzed the effect of sophistication on DB. However, even if there are many studies on DB the results are mixed and neither the literature could come up with a definite result on the reasoning behind the disposition bias nor the effects of the disposition bias on different groups. Seeing this gap in the literature in our paper we constructed a methodology on analyzing disposition bias through subgroups of investors with newly defined proxies. Our aim is to understand the reasoning behind the differences of the size of disposition bias. For example, we know from literature that not all women or men are exposed to disposition bias but we do not know the determinant of this difference. We know that institutional investors are less exposed to DB but we cannot generalize this to all institutional investors. If we can understand the reasoning behind this difference we can come up with important policy recommendation to reduce this bias, and reduce the wealth reduction effect of DB on investors. Motivated by the above arguments, we perform an analysis on the existence and equivalence of disposition bias across investors. Our main research questions are as follows. Do investors have a disposition bias when grouped in terms of their type, i.e. their gender or status (male, female and legal person); size (small, medium sized and large) and trading frequency (infrequently, occasionally and frequently trading)? Is the disposition effect the same across different groups as well as subgroups, i.e. when their different features are jointly considered? To answer those questions we used an improved methodology on the classification of the subgroups. This was an important gap in disposition bias literature, because there were different proxies on trading size and trading frequency. For instance, when classifying for size, many researchers such as Grindblatt and Keloharju (2001), Brown et al. (2006), Dhar and Zhu (2006), Weber and Welfens (2008) refer to investors' overall portfolio value or asset value (i.e., the value of their portfolio at an instant or an average portfolio value over a time period). Yet, these overall or average values have some limitations in capturing the true size of investors. Similarly, trading frequency is usually measured with average number of trades for a time period as of Lehenkari and Perttunen (2005), Dhar and Zhu (2006), Chen et al. (2007) and others. Indeed, if an investor trades actively at some period but less in others, this means that he/she always keeps a potential to trade actively. An average number, therefore, does not necessarily reflect his/her attitude. Based on this idea we developed new proxies for both trading size and trading frequency benefiting from the intraday investor base data. We calculated the disposition effect both base on numbers and values as of Barber et al. (2007) where many other studies preferred to make their analysis based on number of DB's. Last but not least we are the first paper which makes the comparative analysis of the group of investors through ANOVA and Tukey HSD test. Our study contributes to the literature in the following ways. Most studies consider a single characteristic of investors in terms of gender, size or trading frequency (e.g., female, small or frequently trading) neglecting joint features such as 'frequently trading small female' investor. To fill this gap we run base-, two- and three-level analyses, i.e. by combining all the investor features (type, size and trading frequency). To the best of our knowledge, such an analysis is unique in the literature and helps shed more light on the disposition bias in investor subcategories. Moreover, we propose better proxies for investor size and trading frequency that seek capturing investor sophistication at an intraday setting (detailed in the Methodology section). Furthermore, our calculation of disposition effect is based on both the 'value' and the 'number' of paper gains and losses. Last but not least; although behavioral biases, and in particular disposition bias, have been widely studied worldwide, a detailed investigation on Turkish market is still missing, the reason presumably being the lack of investor level data for research. An exception includes Tekçe et al. (2016) that examines the determinants of various biases of individual investors such as age, gender, experience, wealth and location. Our dataset encompasses the whole investor base in the country (we start with a sample of 462,488 investors and end up with 283,913, after extracting noisy data). Hence, we can catch a large portion of investor activity. In addition, the descriptive statistics obtained on a large dataset reflects the distribution and general characteristics of investors in terms of gender or status, size and trading frequency in Borsa Istanbul.