Hadi Gökçen

• Doctor of Philosophy
• Professor at Gazi University

Population growth, rapid developments in technology, increase in living standards, changes in the household structure and economic structure of societies, and the increase in urbanization at very high rates, as well as the increase in the demand for renting or purchasing real estate, have both expanded the real estate market and made it more active...

In this study, a measurement tool was developed to measure the digital transformation perceptions of defense industry company employees and the components that determine the digital transformation perception were investigated. The developed digital transformation (DTP) scale consists of 28 items with a five-factor structure. DPT consists of busines...

TCDD, 2003 yılında Yüksek Hızlı Tren (YHT) hatlarını ilk olarak Ankara-Eskişehir arasında döşemeye başlamıştır. 13 Mart 2009 tarihinde Ankara-Eskişehir hattının ticari seferlere açılması ile birlikte hızlı tren işletmeciliğine geçilmiştir. Seferler Ankara-Eskişehir arası 2 gidiş 2 geliş olmak üzere günde toplam 4 sefer ile başlamış olup, 04.05.2024...

As technology advances, the integration of robots in the assembly line has become widespread. While robots offer numerous benefits, such as increased productivity and improved product quality, they also result in higher energy usage. Finding the optimal line balance while considering energy consumption is a challenging task in a robotic assembly li...

In recent years, the spread of disinformation, which is one of the kind of information pollution, has accelerated on online social media platforms, and detecting disinformation early has become significant to be able to remove the negative impact it has on individuals and societies. In this direction, increased number of studies focusing on the aut...

Remote sensing data, whose dimensions increase exponentially and turn into big data with the new technologies, cause significant difficulties in transferring, storing, and processing because of consisting of gigantic coarse-grained files. This article proposes a novel two-phase big data management system on the geo-distributed private cloud that ta...

This study involves an integrated approach consisting of the Fuzzy AEW Method which considers all relevant criteria and involves the contribution of all members of a strategic planning team in the determination of strategic goals as well as the Fuzzy Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) method. The Fuzzy AEW meth...

With the rise of social media platforms, which have billions of users around the World, the dissemination of information has become easier than ever. The COVID-19 pandemic has increased the use of social media to discuss many topics, including vaccines. The aim of this study is to analyze public sentiment with Machine Learning of vaccine-related tw...

The increase in the human population in the world, the rapid rate of digitization, the support of more services using digital technology during this transformation, and the increase in the number of users lead to the emergence of large volumes of data and information. In the global context, it is one of the most important problems of today to produ...

The increase in the human population in the world, the rapid rate of digitization, the support of more services using digital technology during this transformation and the increase in the number of users lead to the emergence of large volumes of data and information. In the global context, it is one of the most important problems of today to produc...

For those who invest in real estate as an investment tool, as well as those who buy and sell real estate, the price of real estate should be predicted realistically and with the highest accuracy. It should be noted that the predict model should be the most appropriate representation of the underlying fundamentals of the market. Otherwise, the mista...

Owning a house is one of the most important decisions that low and middle income people make in their lives. The real estate market is a significant factor of the national economy as much as it is important for individuals. Therefore, predicting real estate values or real estate valuation is beneficial and necessary not only for buyers, but also fo...

Anomaly detection is the process of identifying patterns that move differently from normal in a certain order. This process is considered one of the necessary measures for the safety of intelligent production systems. This study proposes a real-time anomaly detection system capable of using and analyzing data in smart production systems consisting...

There are some indexes that affect the quality of life of countries. Economic crises, pandemics, natural events, etc. affect these indexes. The COVID-19 pandemic also had a direct impact on all these indexes. In this study, the impact of the COVID-19 pandemic on the quality of life of countries was investigated. In this context, 29 different artifi...

Yalın düşüncenin amacı, mümkün olduğunca fazla israftan kurtulmaktır. Taşıma, aşırı üretim, bekleme, uygunsuz malzemeler, aşırı işleme, envanter ve hareket gibi katma değeri olmayan faaliyetleri ortadan kaldırmak, başarılı bir şirketin en önemli ön koşullarından biridir. Bu kavram, yalın düşüncenin ayrılmaz bir parçasıdır ve karlılığı artırmaya yar...

Sosyal medya platformlarında kullanıcıların paylaşımlar arasında saldırgan dil barındıran içeriklerin önemli oranda arttığı gözlemlenmiştir. Çalışma Türkçe dilinde bu sorunun çözümüne katkı sağlamayı amaçlamaktadır. Bu çalışmada Twitter platformundan elde edilen bir veri seti oluşturulmuştur. 14752 Türkçe tweet metninden oluşan bu veri seti etiketl...

As there are indicators that affect the performance criteria of businesses, countries also have some indicators that affect the quality of life. Indicators affecting the quality of life; which are property, pollution, health care, crime, traffic, and cost of living index. These indexes are created by analyzing data entered by citizens. Economic cri...

The increase in the number of lawyers in our country in recent years has led to the emergence of large law offices where many lawyers are employed. These offices have a greater number of cases and diversity of cases compared to offices with a small number of lawyers. It is seen that the said offices are faced with problems such as which of the many...

The primary focus of lean thinking is to prevent waste. Overproduction, unnecessary transportation, unnecessary movement, unnecessary waiting, unnecessary processing, excess inventory and errors are defined as 7 wastes. It is aimed to prevent waste by finding the number of picking boxes along with the shortest path in the warehouse of the personnel...

Universities occupy an important place in the training of qualified manpower needed by a country, in the production of knowledge and in service to the society with the educational services they provide. Due to the limited capacity and increasing demand in higher education, distance education (DE) programs in universities are spreading rapidly. In t...

Günümüzde üretilen veri boyutu çok yüksek miktardadır. Bu yüksek boyutlu veri genellikle “Büyük Veri” olarak adlandırılır. Büyük verilerin önemli bir kısmı metin verilerinden oluşur. Bu nedenle, metin işlemenin önemi de her geçen gün artmaktadır. Sosyal medya büyük veri kaynaklarının en önemlilerinden bir tanesidir. Twitter ise en yaygın kullanılan...

Unmanned Combat Aerial Vehicles are defense systems based on artificial intelligence which is intensively used by many countries to provide national security on military operations. By means of these systems, moving or non-moving threat factors in the operation field could be destroyed under harsh and challenging geographical conditions without req...

Abstract: Universities contribute to both regional and global development with the knowledge they produce and the qualified manpower they raise. Universities open formal and distance education (DE) programs and develop new programs to meet the needs of individuals and the community. In order to develop new programs and make the existing programs mo...

Birimler arasında sağlıklı veri akışının sağlanması ile dijitalleşen üretim sistemleri ve bu dijitalleşme süreci doğrultusunda otomatikleşen zeki fabrika yapıları gün geçtikçe üretim endüstrisinde kendisine daha fazla yer bulmaktadır. Bu tür sistemler, üretim önemli gelişmeler ve teknolojik ilerlemeler sağlamış olsa da çeşitli sorunları da beraberi...

Teknolojinin hızla geliştiği son yıllarda kablonun sınırlarından kurtulma ve aynı anda kablosuz birçok cihaza bağlanma isteği yeni teknolojilerin geliştirilmesine neden olmuştur. Mobil telefonlar, bilgisayar ile yapılabilecek her türlü işlemi gerçekleştirebilme olanağı sağlamanın yanında zeki özellikleri ile internete erişim imkânı sağlaması sayesi...

Özet-Endüstri 4.0 son zamanların en popüler konularından biri olmayı sürdürmektedir. Bünyesinde, zeki fabrika sistemleri, kendi aralarında otomatik iletişim kurarak süreci yönetebilen makineler ve ortaya çıkan zeki ürünler bulundurduğu için ilgi alanında kalmaya devam edecektir. Ancak, yeni nesil endüstri devrimi kapsamında ele alınan uygulamalar,...

Purpose This research aims to address the cost-oriented stochastic assembly line balancing problem (ALBP) and propose a chance-constrained programming model. Design/methodology/approach The cost-oriented stochastic ALBP is solved for small- to medium-sized problems. Owing to the non-deterministic polynomial-time (NP)-hardness problem, a multiple r...

In this paper, we introduce a new variant of Location Routing Problem with the name of “Location Routing Problem with Arc Time Windows” (LRP_ATW), which emerges from the need of “safe transportation” in terror zones. In this specific problem, there are “arc time windows” on the arcs (roads) for transferring the vehicles like trucks and articulated...

This paper is aimed to investigate application potential of data mining in automotive industry. Most important usage and driving parameters, which effects fuel consumption and emission level of passenger cars identified and classified by using data mining methods. A dataset created by combining Euro 6 data of passenger cars has been analyzed using...

This paper is aimed to investigate application potential of data mining in automotive industry. Most important usage and driving parameters, which effects fuel consumption and emission level of passenger cars identified and classified by using data mining methods. A dataset created by combining Euro 6 data of passenger cars has been analyzed using...

There are legislations encumbering manufacturers to incorporate environmental factors into their decisions in several industries. Automotive is one of these sectors and in many countries, particularly in those who are a member of the European Union, there are regulations to guarantee the recycling of end-of-life vehicles (ELVs). In Turkey, recovery...

This study incorporates ergonomics and resource restrictions into assembly line balancing (ALB). For this purpose, an integrated model is proposed. The proposed model is essentially a cost-oriented formulation for ALB under psychological strain, physical strain, worker skills, multiple workers, equipment, working postures and illumination level res...

Isletmelerde ekonomik calisma gereginin buyuk onem tasidigi gunumuzde, kaynaklarin etkin olarak kullanilip degerlendirilmesi oldukca onemli bir konudur. Bu nedenle montaj hatlarinda maliyetlerin azaltilmasi ve is gucu gibi kaynaklardan verimli sekilde faydalanmak zorunluk hale gelmistir. Bu makalede Maliyet Tabanli Stokastik Montaj Hatti dengeleme...

This paper proposes a mixed integer programming model for a closed-loop supply chain (CLSC) network with multi-periods and multi-parts under two main policies as secondary market pricing and incremental incentive policies. In the first policy, customers order and receive products from distribution centres, but at next period, they can trade among t...

In today's business that need for economic studies are significant, evaluation and effective use of resources is a very important issue. Therefore, in assembly lines, reduction of costs and benefit from resources such as labor efficiently has become imperative. In this paper the chance constraint mathematical model for stochastic cost oriented asse...

Nowadays, with the large increase in fossil energy consumption on the environment and human health effects are increasing with each day. When fossil fuels are burned, it releases greenhouse gases one of the important is the carbon dioxide (CO2). In this study, for a total of 20 countries energy sources (renewable and fossil energy) with the use of...

In this paper, we introduce a new variant of the Vehicle Routing Problem (VRP), namely the Two-Stage Vehicle Routing Problem with Arc Time Windows (TS_VRP_ATWs) which generally emerges from both military and civilian transportation. The TS_VRP_ATW is defined as finding the vehicle routes in such a way that each arc of the routes is available only d...

Supply chain management operates at three levels, strategic, tactical and operational. While the strategic approach generally pertains to the optimisation of network resources such as designing networks, location and determination of the number of facilities, etc., tactical decisions deal with the mid-term, including production levels at all plants...

Reverse logistics has received growing attention throughout this decade because of the increasing environmental concern, government regulations and economical reasons. The design of reverse logistics network is one of the most important and challenging problems in the field of reverse logistics. This paper proposes a capacitated, multi-echelon, mul...

Bu makalede; özellikle mal üreten sistemlerde bilinen Montaj Hattı Dengeleme (MHD) metodlarının hizmet üreten sistemlere uygulanabilirliği incelenmiştir. Bu amaç doğrultusunda müşterilere tedavi hizmeti üreten bir Fizik Tedavi ve Rehabilitasyon Kliniğinde uygulama çalışması yapılmıştır. Hastalara sunulan standart hizmetlerin her biri bir ürün çeşid...

U-type and two-sided assembly lines are two types of design having advantages over traditional straight assembly lines. In this paper, a new line design hybrid of U-type and two-sided lines is presented. A bi-objective 0-1 integer programming model is developed to solve the line balancing problem of the proposed design. Zoning constraints are also...

The End Stage Renal Disease (ESRD) as a chronical health problem requires an expensive and a lifetime treatment called hemodialysis. It is important to obtain new information in order to reduce the cost of the treatment and to improve the quality of patient's life. Treatment period requires a lot of clinical tests related to the risk factors for mo...

In this paper, a simulated annealing approach is developed for the parallel mixed-model assembly line balancing and model sequencing (PMMAL/BS) problem which is an extension of the parallel assembly line balancing (PALB) problem introduced by Gökçen et al. (200624. Gökçen , H and Ağpak , K . 2006 . A goal programming approach to simple U-line balan...

Two-sided assembly lines are usually designed to produce large-sized products such as automobiles, trucks and buses. In this type of production line, both left-side and right-side of the line are used. In parallel assembly lines, one or more product types are produced on two or more assembly lines located in parallel to each other. Both production...

Traditional straight assembly lines are still one of the most important elements and an important fact of today's production systems. If applicable, a company can combine its multiple straight assembly lines and obtain many advantages of Shojinka more or less. This paper analyses a new problem – integrated balancing of multiple straight assembly li...

Balancing parallel assembly lines provides flexibility to minimise the total idle times of assembly lines and the total number of workstations required in production facilities. This paper proposes two goal programming approaches to balance parallel assembly lines with precise and fuzzy goals. Three conflicting goals, namely number of workstations,...

Production systems which has more than one assembly line is widely seen in industry. These lines produce same or similar products, and their cycle times are generally considered similar. So, Gökçen et al. (2006) suggested to combine workload of some stations on parallel consecutive lines, in a convenient way, for improving the resource utilization...

Cited By (since 1996):3, Export Date: 8 January 2014, Source: Scopus

In a production facility there may be more than one straight assembly line located in parallel. Balancing of parallel assembly lines will provide the flexibility to minimize the total number of workstations due to common resource. This type of problem is called as parallel assembly line balancing (PALB) problem. In this paper, a tabu search based a...

The importance of studying public service systems and finding robust solutions to the problems encountered in public service management has increased considerably over the past decade. One of the main objectives is to find acceptable solutions to Public Service Problems (PSPs) within an affordable period of time. However, many PSPs remain difficult...

Recently, there has been a growing interest in reverse logistics due to environmental deterioration. Firms incorporate reverse flow to their systems for such reasons as ecological and economic factors, government regulations and social responsibilities. In this paper a new mixed integer mathematical model for a remanufacturing system, which include...

Nowadays, firms incorporate reverse flow to their systems because of some reasons such as economic and ecologic reasons, regulations from government, social responsibilities. These firms face to some problems such as designing efficient reverse logistics network and managing the reverse flow of materials, components or products. A generic reverse l...

Assignment of military personnel to positions is very demanding, primarily a manual process performed by detailers. Detailers try to satisfy needs and preferences of commands and personnel. In this paper, an analytic hierarchy process (AHP) and two sided matching based Decision Support System is proposed to assist detailers. The DSS is programmed t...

In today's databases, large-volume data can be managed. It is impossible to figure out such a huge data without contribution of computers. In order to cope with this problem, OLAP used for summarizing, integrating, and analyzing large scale data bases. Flexible reporting and fast query can be performed by utilizing OLAP architecture. While some bas...

In this paper, an integer programming model for the hierarchical workforce problem under the compressed workweeks is developed. The model is based on the integer programming formulation developed by Billionnet [A. Billionnet, Integer programming to schedule a hierarchical workforce with variable demands, European Journal of Operational Research 114...

Gökçen et al. (2006) have proposed several procedures and a mathematical model on single-model (product) assembly line balancing (ALB) problem with parallel lines. In parallel ALB problem, the goal is to balance more than one assembly line together. In this paper, a network model for parallel ALB problem has been proposed and illustrated on a nu...

In this paper, chance-constrained 0–1 integer programming models for the stochastic traditional and U-type line balancing (ULB) problem are developed. These models are solved for several test problems that are well known in the literature and the computational results are given. In addition, a goal programming approach is presented in order to incr...

Productivity improvement in assembly lines is very important because it increases capacity and reduces cost. If the capacity of the line is insufficient, one possible way to increase the capacity is to construct parallel lines. In this study, new procedures and a mathematical model on the single model assembly line balancing problem with parallel l...

In this paper, a goal programming model for the simple U-line balancing (ULB) problem is developed. The model is based on the integer programming formulation developed by Urban [Urban, Note: Optimal balancing of U-shaped assembly lines, Management Science 44(5) (1998) 738–741] for the ULB problem and the goal model of Deckro and Rangachari [Deckro,...

In this paper, a shortest route formulation of simple U-type assembly line balancing (SULB) problem is presented and illustrated on a numerical example. This model is based on the shortest route model developed in [Manage. Sci. 11 (2) (1964) 308.] for the traditional single model assembly line balancing problem.

In this paper, a new approach on traditional assembly line balancing problem is presented. The goal of proposed approach is to establish balance of the assembly line with minimum number of station and resources. For this purpose, 0–1 integer-programming models are developed. These models are solved using GAMS-CPLEX mathematical programming software...

In this paper, a new heuristic procedure for single model U-line balancing problem with stochastic task time is proposed. The proposed procedure is based on the COMSOAL method developed by Arcus for traditional deterministic single model assembly lines. The aim of the procedure is to assign tasks to stations such that number of station will be mini...

Managers spend the most of their times to making decisions. Making correct and consistent decision, depend on producing required information, This is possible by constructing the information systems. Decision support systems (DSS) is an Information system and provide the support to the decision makers for especially decisions with high degree of un...

A shortest-route formulation of the mixed-model assembly line balancing problem is presented. Common tasks across models are assumed to exist and these tasks are performed in the same stations. The formulation is based on an algorithm which solves the single-model version of the problem. The mixed-model system is transformed into a single-model sys...

This study is based on investigating the effect of incompleted tasks on the line efficiency after balancing the stochastic ALB problem. For this purpose, a model allowing buffer storage between the stations in order to reduce the effect of incompleted tasks, is proposed.

The assembly line balancing problem has been a focus of interest to the academicians of production/operations management for the last 40 years. Although there are numerous studies published on the various aspects of the problem, the number of studies on mixed-model assembly lines are relatively small. In this paper, a binary integer programming mod...

In this paper, a binary goal programming model for the mixed-model assembly line balancing (ALB) problem is developed. The model is based on the concepts developed by Patterson and Albracht [1] and the model of Deckro and Rangachari [2] developed for the single-model ALB problem. The proposed model provides a considerable amount of flexibility to t...

In this paper, a new heuristic procedure for single model U-line balancing problem with stochastic task time is proposed. The proposed procedure is based on the COMSOAL method developed by Arcus (16) for traditional deterministic single model assembly lines. The aim of the procedure is to assign tasks to stations such that number of station will be...