Berna Dengiz

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Papers by Berna Dengiz

Design of Reliable Communication Networks: A Hybrid Ant Colony Optimization Algorithm

by Önder Belgin, Berna Dengiz, and Fulya Altiparmak

This article proposes a hybrid approach based on Ant Colony Optimization (ACO) and Simulated Anne... more This article proposes a hybrid approach based on Ant Colony Optimization (ACO) and Simulated Annealing (SA), called ACO SA, for the design of communication networks. The design problem is to find the optimal network topology for which the total cost is a minimum and the all-terminal reliability is not less than a given level of reliability. The proposed ACO SA has the advantages of the ability to find higher performance solutions, created by the ACO, and the ability to jump out of local minima to find better solutions, created by the SA. The effectiveness of ACO SA is investigated by comparing its results with those obtained by individual application of SA and ACO, which are basic forms of ACO SA, two different genetic algorithms and a probabilistic solution discovery algorithm given in the literature for the design problem. Computational results show that ACO SA has a better performance than its basic forms and the investigated heuristic approaches.

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Simulation optimization using tabu search

2000 Winter Simulation Conference Proceedings (Cat. No.00CH37165), Nov 11, 2002

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Kesirli üniversal kriging meta-modeli

Journal of The Faculty of Engineering and Architecture of Gazi University, Feb 28, 2022

 Validation of Fractional Universal Kriging metamodel for expensive simulation output modelling.... more  Validation of Fractional Universal Kriging metamodel for expensive simulation output modelling.  Highly nonlinear inputoutput relation analysis of the experiments.  Latin hypercube design and correlogram analysis for the experiment. The Fractional Universal Kriging metamodel is an extension of the Universal Kriging metamodel proposed for situations where the drift function structure is unknown. It is proposed to use a power function of variables that can also take fractional values, instead of first and second order regression models as a drift function in the Fractional Universal Kriging metamodel. According to results given in Table A, considering the performance criteria of mean squared error, Ordinary Kriging metamodel for Adjiman function, Universal Kriging (quadratic drift) metamodel for Deckkers-Aarts function and Fractional Universal Kriging metamodel for all other test functions provide superior predictions on the validation data sets. Table A. MSE of the kriging metamodels Metamodel Name Function Name MSE Ordinary Kriging A d jiman 0.031 Universal Kriging(quadratic) Deckkers-Aarts 7.5

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Personel Atama Problemi: Bir Kamu Kurumu Uygulaması

Personel atama problemi genel olarak tane personelin adet görev eşleştirilmesi olarak tanımlanabi... more Personel atama problemi genel olarak tane personelin adet görev eşleştirilmesi olarak tanımlanabilir. Atama problemi 1950'li yıllardan günümüze kadar birçok alanda karşımıza çıkmaktadır. Atama maliyetleri, personel tercihleri, hizmet puanları, personel ve görev nitelikleri gibi kurumdan kuruma değişen atama kriterlerine göre personel atamaları yapılmaktadır. Bu çalışmada; Türkiye'de güvenlik hizmeti veren bir kamu kurumunun atama sistemini dikkate alan atama problemi tanımlanmıştır. Çalışma; sosyal gelişmişlik, mesafe, okul/eğitim durumu vb. birçok sebeple personelce tercih edilmeyen görev kadrolarına hakkaniyetli bir şekilde personelin atanması için, yeni ve dengeli bir atama modelini hedeflemiştir. Küçük ve tercih edilmeyen yerleşim yerlerindeki görevlerde çalışan personelin gelişmiş ve çok tercih edilen yerleşim yerlerindeki görevlere, gelişmiş ve çok tercih edilen yerleşim yerlerindeki görevlerde çalışan personelin ise küçük ve tercih edilmeyen yerleşim yerlerindeki görevlere atanması için bölgeler arası rotasyonu sağlayan, bir atama modeli önerilmiştir. Literatürdeki çalışmalarda kullanılan "birikimli hizmet puanı" yerine "ortalama hizmet puanları" ile "görev yeri puanları" birlikte kullanılmıştır. Hizmet puanı ve görev puanlarında oluşan denge ile kritik olup tercih edilmeyen görevlere tecrübeli personelin atanması sağlanacaktır. Ayrıca bu model ile karar vericiye toplam atama maliyetinde ve personelin öncelikli tercihlerine atanması konusunda alternatif seçenekler sunulmaktadır. Önerilen matematiksel model ile kurumun atama problemi çözülmüş ve hesaplamalı analiz sonuçları sunulmuştur.

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A Network-Based Genetic Algorithm for Design of Communication Networks

日本設備管理学会誌, Feb 1, 2004

AEEE tahmini ve toplama noktalarının belirlenmesi: Çankaya Belediyesi için bir uygulama

DOAJ (DOAJ: Directory of Open Access Journals), Aug 1, 2018

Elektrikli ve elektronik cihazlar (e-eşya), kullanım ömürleri tamamlandığında elektrikli ve elekt... more Elektrikli ve elektronik cihazlar (e-eşya), kullanım ömürleri tamamlandığında elektrikli ve elektronik atığa (AEEE) dönüşmektedir. AEEE'ler atıldıklarında, yakıldıklarında veya geri dönüşüm için parçalandıklarında tehlikeli maddeler içeren ürünlere dönüşerek çevreye ve insan sağlığına zarar vermektedir. AEEE'lerin zararlarını en aza indirmek ve geri dönüşümlerinden ekonomik fayda sağlamak amacıyla belediyeler tarafından uygun şekilde toplanması, taşınması ve işlenmesi gerekmektedir. Bu çalışmada, Çankaya İlçesi Çevre Koruma ve Kontrol Müdürlüğü işbirliği ile Çankaya Belediyesi için AEEE yönetimine destek olacak bir çalışma gerçekleştirilmiştir. Çalışma kapsamında ilk olarak Çankaya ilçesi için AEEE miktarları televizyon, buzdolabı, çamaşır makinesi, fırın ve elektrikli süpürge için kullanıcı davranışları dikkate alınarak tahmin edilmiştir. Daha sonra AEEE toplama noktalarının belirlenmesi için yer seçimi problemi bir küme örtme problemi olarak ele alınmış ve çözülmüştür.

Belirsizlik altında kaynak kısıtlı çok modlu çoklu proje çizelgeleme

Stokastik montaj hattı dengeleme: Bir tavlama benzetimi algoritması

Endüstri Mühendisliği, 2001

The location-routing problem with simultaneous pickup and delivery: Formulations and a heuristic approach

Omega, Aug 1, 2012

ABSTRACT In this paper, we consider a variant of the Location-Routing Problem (LRP), namely the L... more ABSTRACT In this paper, we consider a variant of the Location-Routing Problem (LRP), namely the LRP with simultaneous pickup and delivery (LRPSPD). The LRPSPD seeks to minimize total cost by simultaneously locating the depots and designing the vehicle routes that satisfy pickup and delivery demand of each customer at the same time. We propose two polynomial-size mixed integer linear programming formulations for the problem and a family of valid inequalities to strengthen the formulations. While the first formulation is a node-based formulation, the second one is a flow-based formulation. Furthermore, we propose a two-phase heuristic approach based on simulated annealing, tp_SA, to solve the large-size LRPSPD and two initialization heuristics to generate an initial solution for the tp_SA. We then empirically evaluate the strengths of the proposed formulations with respect to their ability to find optimal solutions or strong lower bounds, and investigate the performance of the proposed heuristic approach. Computational results show that the flow-based formulation performs better than the node-based formulation in terms of the solution quality and the computation time on small-size problems. However, the node-based formulation can yield competitive lower bounds in a reasonable amount of time on medium-size problems. Meantime, the proposed heuristic approach is computationally efficient in finding good quality solutions for the LRPSPD.

Two new mathematical models for two level electricity network design with distributed generation

Turkish Journal of Electrical Engineering and Computer Sciences, 2023

In the new millennium, traditional electrical power systems have undergone a significant change d... more In the new millennium, traditional electrical power systems have undergone a significant change driven by a set of requirements arising from evolving and changing technology. Thus, fundamental changes have occurred in the way electrical energy is produced, transmitted, and distributed. This situation has revealed the need to expand existing networks or to establish new networks. The available literature revealed that particular attention to the latter one is still limited due to the complexity of the power system. The purpose of this study is to contribute to the body of literature that tries to address the gap at overall design of a power distribution network. Moreover, distributed generation integration is also considered simultaneously with network design. In this paper, a two-level electricity distribution system design with distributed generation (TLEDS_DG) for green-field planning is considered. The TLEDS_DG is defined to find the locations of distribution transformers, to decide the number of distributed generators, and to design underlying two-level network in such a way that demand and capacity constraints are satisfied, and the overall design cost is minimized. Two mathematical models, a node-based and flow-based, are proposed and compared in terms of solution quality and CPU times. Within the flow-based formulation which is a new technique, called node cloning, is used to transform a two-level network into a single-level one. To validate the effectiveness and efficiency of the proposed approach (flowbased formulation with node cloning), we conduct numerical studies based on randomly generated instances up to 300 customers. Additionally, sensitivity analysis is also applied to demonstrate the impacts of initial parameter settings. Computational results on a large suite of test problems show that the proposed approach (flow-based formulation with node cloning) is efficient and highly effective for the generated test problems.

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Applications of Deep Learning Techniques to Wood Anomaly Detection

Springer eBooks, 2022

Simulation optimization using tabu search

Winter Simulation Conference, Dec 10, 2000

Investigation of the performance and operation of complex systems in manufacturing or other envir... more Investigation of the performance and operation of complex systems in manufacturing or other environments, analytical models of these systems become very complicated. Because of the complex stochastic characteristic of the systems, simulation is used as a tool to analyze them. The trust of such simulation analysis usually is to determine the optimum combination of factors that effect the considered system performance. The purpose of this study is to use a tabu search algorithm in conjunction with a simulation model of a JIT system to find the optimum number of kanbans.

format_quoteThe study compares TS and RS algorithms in solving kanban optimization, providing insights into their relative effectiveness on solution searches.format_quote

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Türki̇ye’De Endüstri̇ Mühendi̇sli̇ği̇ne Bi̇r Bakiş: Geçmi̇şi̇, Bugünü Ve Geleceği̇

Verimlilik dergisi, Jul 30, 2022

Bu yazıda mevcut verilere dayalı olarak Endüstri Mühendisliği (EM)'nin Türkiye'deki tarihsel geli... more Bu yazıda mevcut verilere dayalı olarak Endüstri Mühendisliği (EM)'nin Türkiye'deki tarihsel gelişimi, bugünkü durumu ve geleceğiyle ilgili bir değerlendirme yapmak, gelecekte yapılacak farklı değerlendirme çalışmaları için bir temel oluşturmak amaçlanmıştır. Yöntem: Literatür taraması yapılmış, mevcut istatistiklerin değerlendirilerek yazarların alanla ilgili deneyim ve bilgi birikimine dayalı öneriler geliştirilmiştir. Bulgular: Bu yazıda "EM'nin Türkiye'de en çok tercih edilen ve geniş bir yelpazede uygulama alanı bulan meslekler" arasında olduğu istatistiklere dayalı olarak ortaya konmuştur. Günümüzde yaşanan hızlı değişime uygun olarak EM'nin bu konumunun sürdürülebilirliğinin nasıl sağlanacağı incelenmiştir. İyileştirmeye açık alanlara, örneğin; Üniversite-Sanayi işbirliği, EM'nin dijitalleşme alanında yerini alması, Z-kuşağı'nın dikkate alınarak eğitim ve öğretim programlarının yenilenmesi, hizmet sektörüne doğru kayan eğilimin imalat sektörüne döndürülmesi gibi konulara dikkat çekilmiştir. Bunlara ek olarak küresel problemlerin örneğin açlık, sağlık, eğitim, girişimcilik-yenilikçilik (inovasyon), sürdürülebilirlik, barış ve demokrasi, ekonomik kalkınma vb. ayırdında olan Endüstri mühendislerinin nasıl yetiştirilebileceği tartışılmıştır. Özgünlük: Türkiye'de EM'nin tarihsel gelişimi başlangıçtan günümüze dek bu boyutta ilk kez ele alınmış ve bu değerlendirme çalışması hazırlsanmıştır.

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A Genetic Algorithm for the Redundancy Allocation Problem with Repairable Components

Lecture notes on data engineering and communications technologies, 2022

Production of Plasma Based Surgical Device for Discectomy Operations and Testing in Novel in-vitro Model

Proceedings of the 2020 10th International Conference on Biomedical Engineering and Technology

In this research, we produced a plasma-based surgical device for operations for spine discectomy.... more In this research, we produced a plasma-based surgical device for operations for spine discectomy. It covers the details of the hardware of focused plasma-based (gas plasma, plasma jet) surgical prototype device manufacturing which will be used in spine discectomy surgery, identification of active device operating conditions with the in vitro tests and evaluation of performance. Human spinal discs material between the vertebra bones may degenerate because of a series of biomechanical and biochemical changes over time. This degeneration and its further state which known as herniation cause nerve compression, pain, sensory deficits, power reduction, and lack of reflexes in humans. Conditions caused by intervertebral disc herniation are a common health problem and cause significant work loss. Low sensitivities of mechanical methods and control challenges, cause recurrence which is one of the biggest problem (to be re-herniation) for this surgery. In this study, the first generation of a portable atmospheric "focused plasma probe" was designed, implemented and its performance has been evaluated for the view of spine discectomy surgery. In the research, primarily, production of a prototype device consisting of high-voltage power supply, bipolar plasma probe, gas supply control unit has been made. High voltage power supply is one of the critical parts of this study and this power supply has been realized by using transformer and MOSFETs connected according to the half-bridge topology. Its power can easily adjustable up to 150 watts by changing its duty cycle and voltage. Then, the effect of power (watt) has been tested at in vitro conditions. A newly designed in-vitro model was developed due to the requirements of spine discectomy. Finally, we developed a new prototype device which has a controllable destruction area with a synthetic polymer which is presented as a tissue model.

Ar-Ge projelerinin sınıflandırılması için doğal Türkçe dil işleme tabanlı yöntem

Gazi Üniversitesi Mühendislik Mimarlık Fakültesi Dergisi

Birçok farklı sektörde metin halinde bulunan verilerden istenilen bilgilerin elde edilmesi için d... more Birçok farklı sektörde metin halinde bulunan verilerden istenilen bilgilerin elde edilmesi için doğal dil işleme, metin madenciliği ve derin öğrenme yöntemleri kullanılmaktadır. Son zamanlarda artan Ar-Ge proje sayıları ve farklılaşan proje faaliyet alanları ile birlikte Ar-Ge projelerinin ait olduğu araştırma alanlarının belirlenmesi ve bu araştırma alanlarına uygun hakemlerin tespitinde yaşanan sıkıntılar nedeniyle projelerin desteklenme süreçleri olumsuz etkilenebilmektedir. Bu makalede, Ar-Ge projelerinin sınıflandırılması amacıyla öncelikli olarak çalışmanın gerçekleştirildiği veri tabanındaki veriler temizlenmiş ve doğal dil tekniklerinden biri olan “Word2Vec” kelime temsili yöntemi ile otomatik özellik öğrenme yaklaşımı kullanılarak özelliklerin sınıflandırılması amacıyla Evrişimsel Sinir Ağları (CNN-Convolutional Neural Network) modelleri oluşturulmaya çalışılmıştır. TUBİTAK Dergipark sitesinden seçilen ve sınıfları belli olan Ar-Ge projeleri ve Ar-Ge proje içeriğine sahip m...

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Investigation of the Importance of Machine Sequence Flexibility on A Flexible Manufacturing System Performance

Gazi University Journal of Science

Machine sequence flexibility is defined as the combination of operation and routing flexibilities... more Machine sequence flexibility is defined as the combination of operation and routing flexibilities in this study. Its importance in the performance level of a flexible manufacturing cell (FMC) is investigated in this study. Studies related to the effects of various flexibility types, such as routing flexibility, are available in the literature. For example, studies related to routing flexibility try to measure the effects of routing flexibility on the performance levels in the operation of manufacturing systems under their own manufacturing environments. Similarly, this study also aims to present a performance measurement model based on Taguchi methods to evaluate the effects of machine sequence flexibility factors on the FMC performance and obtain an optimum and robust performance level. Two crucial responses, such as manufacturing lead time (MLT) and surface roughness (SR) are analysed to optimize the FMC performance. Robot speed, cutting tool type, and work-part material type are ...

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Performance enhancement of production systems using fuzzy based availability analysis and simulation method

European J. of Industrial Engineering, 2020

Due to the complexity of today's engineering systems, accurate system performance analysis is imp... more Due to the complexity of today's engineering systems, accurate system performance analysis is important to obtain a more productive system design. This study introduces a new approach to obtain a new system design considering system availability to increase its productivity in a more consistent and logical manner. To obtain more productive system design, both fuzzy availability analysis and simulation are used together. The conventional simulation modelling can be used to analyse the system behaviour considering failure and repair data to predict system throughput. This approach solves the problems of scarce data for failures and repairs in the system. The fuzzy availability analysis is used to consider system failures and repairs based on fuzzy set theory. In other words, the integration of simulation results and fuzzy system availability allows for analysing system performance to improve system productivity with new system design even though system failure and repair data are scarce. This new approach has been applied to improve system productivity in a battery production company in Turkey. The analysis results show that this new approach is able to analyse system performance accurately and improve system productivity with a new system design. [

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Genel amaçlı arama algoritmaları ile benzetim eniyilemesi:En iyi kanban sayısının bulunması

Endüstri Mühendisliği, 2005

ÖZET Gerçek hayatta karşılaşılan sistemler büyük boyutlu ve karmaşık olup birtakım belirsizlikler... more

Traveling Repairmen Problem: A Biogeography-Based Optimization

Lecture notes on data engineering and communications technologies, 2022

Berna Dengiz

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