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https://hdl.handle.net/20.500.12491/145

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Analysis of key attributes of wooden toys via an interval-valued spherical fuzzy analytic hierarchy process
(University of Zagreb, Faculty of Forestry, 2023) Singer, Hilal; Özşahin, Şükrü
& BULL; The evaluation of wooden toys is a complicated process and can be overwhelming for decision -makers in the presence of many conflicting criteria. Hence, this study proposes a fuzzy decision-making model to identify and prioritize the key attributes of wooden toys. For this purpose, the interval-valued spherical fuzzy analytic hierarchy process (AHP), which is one of the fuzzy multicriteria decision-making methods, is applied to obtain weight vectors. Firstly, the wooden toy evaluation problem is formulated as a multicriteria decision-making problem. Then five main criteria and twenty subcriteria are defined with the help of experts. The decision-making team carries out the pairwise comparisons of the criteria. As a result, the priority weights are computed and the ranking order of the criteria is revealed. Additionally, the validity of the obtained results is supported by conduct-ing a comparative analysis between other popular fuzzy methods: interval type-2 fuzzy AHP, interval-valued Py-thagorean fuzzy AHP, and spherical fuzzy AHP. According to the modeling results, the most important criteria are absence of small parts and sharp edges, free of harmful wood preservatives and paints, workmanship qual-ity, contribution to psychomotor development, and contribution to cognitive development. The proposed framework can be adapted to similar decision processes for the evaluation or improvement of toys. Consequently, the findings of this research will help manufacturers, designers, and consumers in making conscious decisions.
Metallic biomaterial assessment via a risk-based decision-making approach
(Gazi Univ, Fac Engineering Architecture, 2022) Singer, Hilal; Özçelik, Tijen Över
This study examined metallic biomaterials via a decision-making approach combining the fuzzy analytic hierarchy process (AHP), the fuzzy failure modes and effects analysis (FMEA), and the fuzzy evaluation based on distance from an average solution (EDAS) method. In the study, stainless steel, titanium, and cobalt-chromium alloys were assessed by employing six main criteria, thirty-one subcriteria, and three risk factors. The fuzzy AHP method was used to determine the importance of the evaluation criteria and risk factors, while the fuzzy EDAS method was employed to analyze the risk priority numbers obtained from the fuzzy FMEA method. According to the results, the first three important criteria were infection, carcinogenicity, and tensile strength. Furthermore, the ranking of the materials in the descending order of the crisp scores was titanium, stainless steel, and cobalt-chromium alloys. Consequently, this study established a foundation for the unbiased assessment and prioritization of current materials.
Applying an interval-valued pythagorean fuzzy analytic hierarchy process to rank factors influencing wooden outdoor furniture selection
(Taylor & Francis Ltd, 2022) Singer, Hilal; Özşahin, Şükrü
Wooden outdoor furniture is a worthwhile investment. When evaluating outdoor furniture, it is important to weigh up decision factors. In situations where there are many conflicting factors, decision-makers become undecided about determining the best furniture option. Hence, this study proposes an interval-valued Pythagorean fuzzy analytic hierarchy process-based model to prioritise the key factors influencing wooden outdoor furniture selection. In light of the aim, five main factors were determined: "safety and health properties", "comfort and appearance properties", "durability and mechanical properties", "economic aspects", and "environmental aspects". Each main factor was then subdivided into various subfactors. Pairwise comparisons were performed to obtain the priorities of the factors. According to the results, "safety and health properties" was the most significant main factor. The most important subfactors were found as "tipping resistance", "environmental friendliness", and "free of harmful substances".
The use of an artificial neural network for predicting the gloss of thermally densified wood veneers
(Inst Forestry Lrcaf, 2022) Özşahin, Şükrü; Singer, Hilal
In this study, an artificial neural network (ANN) model was developed to predict the gloss of thermally densified wood veneers. A custom application created with MATLAB codes was employed for the development of the multilayer feed-forward ANN model. The wood species, temperature, pressure, measurement direction, and angle of incidence were considered as the model inputs, while the gloss was the output of the ANN model. Model performance was evaluated by using the mean absolute percentage error (MAPE), the root mean square error (RMSE), and the coefficient of determination (R-2). It was observed that the ANN model yielded very satisfactory results with acceptable deviations. The MAPE, RMSE, and R-2 values of the testing period of the ANN model were found as 8.556%, 1.245, and 0.9814, respectively. Consequently, this study could be useful for the wood industry to predict the gloss with a smaller number of labour consuming experimental activities.
Prediction of noise emission in the machining of wood materials by means of an artificial neural network
(Scion, 2022) Özşahin, Şükrü; Singer, Hilal
Background: Noise produced during machining of wood materials can be a source of harm to workers and an environmental hazard. Understanding the factors that contribute to this noise will aid the development of mitigation strategies. In this study, an artificial neural network (ANN) model was developed to model the effects of wood species, cutting width, number of blades, and cutting depth on noise emission in the machining process. Methods: A custom application created with MATLAB codes was used for the development of the multilayer feed-forward ANN model. Model performance was evaluated by numerical indicators such as MAPE, RMSE, and R-2. Results: The ANN model performed well with acceptable deviations. The MANE, RMSE, and R-2 values were 0.553%, 0.600, and 0.9824, respectively, in the testing phase. Furthermore, this study predicted the intermediate values not provided from the experimental study. The model predicted that lower noise emissions would occur with decreased cutting width and cutting depth. Conclusions: ANNs are quite effective in predicting the noise emission. Practitioners relying on the ANN approach for investigating the effects of various factors on noise emission can save time and costs by reducing the number of experimental combinations studied to generate predictive models.
The impact of information sharing on different performance indicators in a multi-level supply chain
(UNIV OSIJEK, TECH FAC, 2021) Türker, Yasemin Altun; Tunacan, Tuğba; Torkul, Orhan
Enterprises can use different methods/principles to obtain competitive advantages. Information sharing (IS) among supply chain (SC) partners is also one of these methods used in enterprises and it has positive effects on overall system performance like reduced inventory level, decreased cost, bullwhip effects and increased profit. In this paper, our aim is to present the impacts of IS on different costs like ordering, holding and penalty costs of each SC member and total system costs in multi SC. We want to show the effects of sharing different types of information simultaneously or separately on SC partners as cost change. Besides, this paper presents the situation of order quantity estimation according to the proximity of actual order quantity in decentralized or centralized demand sharing. A model is developed to determine IS influence on the cost of SC partners. Various IS scenarios are studied in this paper. The customer demand, warehouse order quantity and warehouse-manufacturer lead time are the shared information of scenarios. Results are tested and analysed by using analysis of variance (ANOVA).The findings of this study show that IS especially simultaneously sharing reduces system costs. Lead time sharing provides the lowest cost between other types of sharing. For every system member, holding cost reduces the most during IS. The more accurate demand forecasting is performed in centralized demand sharing compared to decentralized sharing.
A multiple criteria analysis of factors influencing surface roughness of wood and wood-based materials in the planing process
(Univ Federal Lavras-Ufla, 2020) Singer, Hilal; Özsahin, Şükrü
This paper presents a study of the fuzzy analytical hierarchy process (FAHP) for the prioritization of factors having important effects on the surface roughness of wood and wood-based materials in the planing process. Firstly, a three-level hierarchical model was devised. Secondly, the FAHP method was employed to determine the weights of the factors. Finally, the prioritization of the factors was carried out taking into account the weights. The results showed that the most significant factors are feed speed (0.300), tool geometry (0.222), and material defect (0.107). Consequently, this study provides a valuable guide to the wood industry to improve the surface quality of wood and wood-based products.
Photocatalytic degradation of yellow 2G dye using titanium dioxide/ultraviolet A light through a Box-Behnken experimental design: Optimization and kinetic study
(Taylor & Francis Inc, 2019) Okçu, Gamze Doğdu; Tunacan, Tuğba; Dikmen, Emre
Yellow 2G (Y2G), a type of anionic, synthetic monoazo dye that is widely used in household applications, textiles, and food industries, has been found to have cardiovascular and neurological effects on all living beings. In the present study, heterogeneous photocatalytic degradation of commercial Y2G was conducted using pure titanium dioxide (TiO2) in a batch reactor system under ultraviolet A (UVA) light for 180 min. TiO2 dosage, pH, and initial Y2G concentration were the three experimental parameters selected and studied to obtain preliminary information about the photocatalytic activities within a specified range. The Box-Behnken design method (BBD) was used to determine optimal values of the results using the above parameters of Y2G photocatalysis under response surface methodology (RSM). The optimum conditions were 0.914 g L-1 TiO2, pH 3.45, and an initial Y2G concentration of 20 mg L-1. The Y2G degradation efficiency was 96.19% using a second-order polynomial equation with R-2 approximate to 0.999. The experimental results also showed that the photocatalytic process could be successfully explained using the modified Langmuir-Hinshelwood model, where k(c) and K-LH were 0.787 mg L-1 min and 0.010 L mg(-1), respectively.
Determination of surface roughness based on the sanding parameters of oriental beech wood
(North Carolina State Univ Dept Wood & Paper Sci, 2018) İlçe, Abdullah Cemil
This study demonstrated the strength of a theoretical model founded on the Box-Behnken experimental design method to determine the surface roughness (R-a parameter) of solid Oriental beech (Fagus orientalis Lipsky) wood. The working parameters (sanding belt grit size of 60 to 100, feeding speed of 4 m/min to 10 m/min, and sanding cutting depth of 0.1 mm to 0.3 mm) of a wide belt sanding machine were determined. The R-a of the samples was experimentally described so that the experimental results were also remodeled with the Box-Behnken method to find the optimum parameters for the lowest R-a. An adjusted correlation factor of 93.6% for the R-a confirmed the compatibility between the experimental and theoretical findings. The high correlation (strength) allowed for a more detailed discussion of the effect of the working parameters on the R-a. The theoretical approach showed that the grit size factor had the largest effect on the R-a compared with the other factors. The optimum parameters were found to be a grit size of 100, feed speed of 4 m/min, and sanding depth of 0.1 mm for a minimum R-a for Oriental beech wood. The experimental data supported these parameters.
An integrated intelligent system for construction industry: A case study of raised floor material
(Vilnius Gediminas Tech Univ, 2018) İlçe, Abdullah Cemil; Özkaya, Kadir
This paper aims to introduce a quantitative method to builders for the most appropriate material selections based on multiple attributes and integrate decision group member opinions throughout bidding process. In this respect, a new model used together with the Analytic Hierarchy Process (AHP) and fuzzy Multi-Objective Optimization on the Basis of Ratio Analysis (MOORA), multi-criteria decision methods are proposed. In a real decision process, there are many uncertainties and ambiguities. In fact decision makers cannot always provide practical guidelines and especially precise judgments due to time limitations. The intelligent model proposed demonstrates that the AHP and fuzzy MOORA approach can not only be used easily to imitate the decision duration in the material selection but also the results obtained from this work provide contractors valuable insight into the material selection problem. At the same time, the quantitative analysis method based on the appropriately raised floor materials along the bidding process enables the builders to use their restricted resources more expeditiously and enhances considerably the possibility of winning agreement, as one of the most striking points deduced from the present study. In short, the model with AHP and fuzzy MOORA approaches can assist the builders to improve resolutions for the bidding.
Mechanical properties of laminated veneer lumber made from ash and red pine woods
(North Carolina State Univ Dept Wood & Paper Sci, 2018) İlçe, Abdullah Cemil
The purpose of this study was to determine the best laminated veneer lumber (LVL) in terms of the density, modulus of rupture (MOR), and elasticity (MOE). This study was planned as a laboratory work for non-structural purpose. LVL were formed with five different layer arrangements (APPPPPA, APPAPPA, APAPAPA, AAPPPAA, and AAPAPAA) using 3-mm thick ash (A) (Fraxinus angustifolia Vahl) and Turkish red pine (P) (Pinus burita Ten.) veneers. Accordingly, the LVL materials (12% +/- 0.5 moisture level) were made and polyvinyl acetate was preferred for bonding the veneers because it was very easy to apply in laboratory applications. The test specimens were conditioned at a relative humidity of 65% +/- 2% and temperature of 20 degrees C +/- 2 degrees C, until attaining a constant mass, at every stage of wood sheets production and before testing. The density, MOR, and MOE tests were conducted according to the conditions specified in different standards. The results confirmed that, as the amount of the solid ash material increased in the LVL, the material had values closer to those of solid ash sample. Additionally, as a result of the experimental measurement results, the best results in terms of the density, MOR, and MOE were achieved with the AAPAPAA-layered LVL.
Usability analysis of different distance measures on TOPSIS
(Gazi Univ, Fac Engineering Architecture, 2017) Kabak, Mehmet; Sağlam, Fatih; Aktaş, Ahmet
In many decision problems, decision makers face with conflicting objectives. In order to solve decision problems with criteria conflicting each other, multiple criteria decision making (MCDM) techniques are applied. This study deals with TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) technique which is a MCDM approach that leads to determine the decision alternative that is the nearest to the positive ideal solution and the furthest to the negative ideal solution. The proposed form of TOPSIS calculates the distance of decision alternatives to positive and negative ideal solutions by using Euclidean distance formula. In the literature, there aren't many studies that analyse the results obtained by using different distance calculation formulas in TOPSIS technique. Thus, in the scope of this study, it is analysed that what kind of differences or similarities can be obtained by using some different distance calculation techniques in the TOPSIS method. The different calculation methods are introduced and the alternative rankings obtained by using these methods are given. It is seen that the best decision alternative does not change for each method, but the ranking of decision alternatives changes. The obtained results show that providing alternative decisions found by using different distance measures in TOPSIS method can support decision makers to make more consistent and meaningful decisions.
A model proposal for locating wind turbines
(Elsevier Science Bv, 2016) Aktaş, Ahmet; Kabak, Mehmet
Total energy demand has increased all around the world in recent years, as a result of growing population and industrialization. Most of the existing sources to generate energy are fossil fuels and it is known that fossil fuels are scarce. In order to satisfy increasing energy demand, searches for new energy generation sources have been conducted and these searches are ended with the proposal of generation of energy by using renewable sources. Decision makers are facing with some important decision problems related to energy generation from renewable sources. In the scope of this study, site selection problem which is one of the most important problems related to renewable energy is considered. Site selection decision consists of many alternatives and many conflicting decision criteria. Due to the hesitance of decision makers in criteria evaluation, a decision making approach based on hesitant fuzzy sets is proposed for solution of the problem. Weights of evaluation criteria for locating wind turbines are obtained by using the proposed decision making approach. (C) 2016 The Authors. Published by Elsevier B.V.
A new evaluation model for service quality of health care systems based on AHP and information axiom
(Ios Press, 2015) Aktaş, Ahmet; Çebi, Selçuk; Temiz, İzzettin
Evaluation of service quality of public hospitals has been largely ignored by health care providers although it is vital for human life. For this, some regulations are being done by Turkish Ministry of Health to improve service quality. One of them is to construct quality teams for hospitals. The other is classification of hospitals into five groups based on their service quality and government provides promotion to hospitals based on this classifications. However, the current classification procedure is not based on an analytical method. Therefore, in the scope of this paper, service quality index has been developed in order to present a scientific basis for classification of hospitals by using multiple criteria decision making tools with respect to existing parameters in the literature. In the scope of this study, service quality parameters are determined and importance degrees of them are obtained by using analytic hierarchy process in terms of service providers and patients. Then, a formulation has been provided to obtain service quality index (SQI) for hospitals. A case study for public hospitals is presented to test applicability of the proposed method.
Analysis of usability in furniture production of wood plastic laminated board
(North Carolina State Univ Dept Wood & Paper Sci, 2015) İlçe, Abdullah Cemil; Budakçı, Mehmet; Özdemir, Serkan; Akkuş, Memiş
The objective of this study was to manufacture a lightweight and easily producible wood plastic laminate (WPL) board that could be used in the furniture sector. Eastern beech (Fagus orientalis L.) veneer papels (A) and hollow polycarbonate boards (B), both with a thickness of 4 mm, were laminated in different combinations using polyurethane (PUR) and polychloroprene (PCR) adhesives. The physical and mechanical properties of the WPL boards obtained were determined according to the principles specified in the EN 326-1, EN 317, EN 310, ASTM D1037, and ASTM D1761 standards. Subsequently, the specimens were compared with particle boards (PB), medium density fiberboards (MDF), and okoume plywoods (PW). According to the results, the AABAA, ABABA, and ABBBA combinations of the WPL materials had better physical properties, such as weight, water absorption, and swelling thickness, compared to the other composites. Furthermore, because the WPL materials had a high bending resistance, modulus of elasticity, and nail and screw withdrawal strength, they could be used instead of PB and MDF. The WPL material obtained within the scope of this study are suitable for furniture making.
Prioritization of factors affecting surface roughness of wood and wood-based materials in CNC machining: a fuzzy analytic hierarchy process model
(Taylor & Francis Ltd, 2020) Singer, Hilal; Özşahin, Şükrü
In this study, the fuzzy analytic hierarchy process was employed to prioritize some factors affecting the surface roughness of wood and wood-based materials in CNC machining. Within the model, four main factors and eighteen subfactors were defined. After constructing the hierarchical structure, the factors were analyzed through experts' opinions. The results demonstrated that wood properties and machining parameters were the most significant main factors. Furthermore, density was found to be the most important subfactor. Consequently, the findings of this study will help the wood industry in enhancing the surface quality of final products.
Selection of softwood species for structural and non-structural timber construction by using the analytic hierarchy process (AHP) and the multiobjective optimization on the basis of ratio analysis (MOORA)
(Institute of Forestry LAMMC, 2019) Özşahin, Şükrü; Singer, Hilal; Temiz, Ali; Yıldırım, İbrahim
In this study, the hybrid approach of the analytic hierarchy process (AHP) and the multi-objective optimization on the basis of ratio analysis (MOORA) was used in order to select the most suitable softwood timber for construction. Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus concorta), red pine (Pinus resinosa), redwood (Sequoia sempervirens), Engelmann spruce (Picea engelmannii), eastern hemlock (Tsuga canadensis), western larch (Larix occidentalis) and western red cedar (Thuja plicata) were evaluated in terms of economic, physical, mechanical, thermal and durability properties. According to the results, the most suitable timbers for structural and non-structural applications were determined to be western larch and redwood, respectively. © 2019, Institute of Forestry LAMMC. All rights reserved.
Development of an artificial neural network model to minimize power consumption in the milling of heat-treated and untreated wood
(2019) Özşahin, Şükrü; Singer, Hilal
Aim of study: The power consumption of machining operations is an important part of the total production cost. Therefore, in this study, an artificial neural network (ANN) model was developed to model the effects of treatment, rotation speed, cutting depth, and feed rate on power consumption in the wood milling process. Material and methods: A multilayer feed-forward ANN was employed for the prediction of power consumption. The accuracy of the model was assessed by performance indicators such as MAPE, RMSE, and R². Main results: It has been observed that the ANN model yielded very satisfactory results with acceptable deviations. The MAPE, RMSE, and R2 values were obtained as 7.533, 0.027, and 0.9737 %, respectively, in the testing phase. Furthermore, it was found that power consumption decreased with decreasing of feed rate and cutting depth. Research highlights: The findings of this study can be used effectively in the forest industry to reduce the experimental time and costs.
Multicriteria evaluation of structural composite lumber products
(2020) Singer, Hilal; Özşahin, Şükrü
In this study, laminated veneer lumber, parallel strand lumber, and laminated strand lumber were evaluated via multicriteria decision-making methods. Within the model, nine evaluation criteria were defined: moisture content, density, bending strength, modulus of elasticity, compression strength parallel to grain, dynamic bending strength, tensile strength parallel to surface, tensile strength perpendicular to surface, and screw holding capacity. The weights of the criteria were computed using the fuzzy analytic hierarchy process (FAHP). The evaluation based on distance from an average solution (EDAS) and the technique for order preference by similarity to an ideal solution (TOPSIS) were employed to determine the ranking of the alternatives. After the borda count method was used, an integrated ranking was obtained. According to the results, the first three important subcriteria were density, bending strength, and modulus of elasticity. Furthermore, laminated veneer lumber was determined as the best alternative. Consequently, this study can present a road map to evaluate wooden materials.
Farklı uzaklık hesaplama yaklaşımlarının TOPSIS üzerinde kullanılabilirliğinin incelenmesi
(2017) Kabak, Mehmet; Sağlam, Fatih; Aktaş, Ahmet
Karar verme problemlerinin çoğunda, karar vericiler birbiriyle çelişen amaçlarla karşılaşırlar. Birden fazla kriterin var olduğu ve kriterlerin birbirleriyle çeliştiği karar problemlerinin çözümünde, çok kriterli karar verme (ÇKKV) yöntemlerinden faydalanılır. Bu çalışmada, pozitif ideal çözüme en yakın, negatif ideal çözüme en uzak karar alternatifini belirlemeye çalışan bir ÇKKV yaklaşımı olan TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) yöntemi ele alınmıştır. TOPSIS yönteminin ilk önerilen halinde, alternatiflerin pozitif ve negatif ideal çözümlere uzaklığı ölçülürken Öklid uzaklık hesaplama yöntemi kullanılmaktadır. Literatürde TOPSIS yönteminde Öklid yerine farklı uzaklık hesaplama yöntemleri kullanıldığında çıkan sonuçları inceleyen çok fazla çalışma yoktur. Bu sebeple bu çalışmada, Öklid uzaklığından ve literatürde ele alınan ölçütlerden farklı bazı uzaklık hesaplama yöntemlerinin TOPSIS yönteminde kullanılmasının, bu yöntemle çözülen bir karar probleminin sonuçlarında ne gibi bir benzerlik/farklılık yarattığı incelenmiştir. TOPSIS yönteminde kullanılabileceği düşünülen uzaklık yöntemleri tanıtılarak, örnek bir uygulama üzerinde oluşan alternatif sıralamaları verilmiş, en iyi karar alternatifi değişmese de karar alternatiflerinin sıralanmasında farklılıklar oluştuğu gözlemlenmiştir. Sonuçlar, TOPSIS yönteminde farklı uzaklık hesaplama teknikleri kullanarak bulunan alternatif kararların karar vericilere sunulması ile daha tutarlı ve anlamlı karar verilmesine destek sağlanabileceğini göstermektedir.

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