Dağ, Tamer

Dağ, Tamer

Name Variants

Dağ, Tamer
T.,Dağ
T. Dağ
Tamer, Dağ
Dag, Tamer
T.,Dag
T. Dag
Tamer, Dag
Tamer Dağ
Da?, Tamer

Job Title

Doç. Dr.

Email Address

Tamer.dag@khas.edu.tr

Main Affiliation

Computer Engineering

Status

Former Staff

Full item page

Sustainable Development Goals Report Points

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Scholarly Output

43

Articles

11

Citation Count

0

Supervised Theses

12 Scholarly Output Search Results

Now showing 1 - 10 of 43

Citation - WoS: 1
Citation - Scopus: 2
Increasing Energy Efficiency of Wsns Through Optimization of Mobile Base Station Locations
(IEEE, 2021) Abbas, Sahar S. A.; Dağ, Tamer; Dag, Tamer; Gucluoglu, Tansal; Computer Engineering
In terms of enhancing overall energy usage, wireless sensor networks (WSNs) can run with minimal energy to extend their lifespan. Due to limited power resources, the optimal base station (BS) location could prolong the overall sensor network's lifetime. In this paper, an algorithm to find the optimal location of BS is proposed. The concept of BS virtual locations grid is used, where BS virtual locations grid within the network's area is created. To find an optimal BS location, the distances between all sensor nodes from virtual locations in the grid are considered, where one of these virtual locations will be chosen as the optimal location. Consequently, BS changes its location to another optimal location each specific number of iteration according to the number of alive sensor nodes within the network (BS mobility). The proposed algorithm is applied to the Stable Election Protocol (SEP) with two and three energy levels. Using the original SEP with two and three energy levels protocols in terms of the network's lifetime and energy consumption, the performance of the algorithm is compared. It is observed that, decreased energy consumption has been achieved, as well as the lifetime of the network has been significantly improved.
Citation - WoS: 1
Citation - Scopus: 4
An Improved Hybrid Stable Election Routing Protocol for Large Scale Wsns
(IEEE, 2021) Hamad, Lana I. S.; Dağ, Tamer; Dag, Tamer; Gucluoglu, Tansal; Computer Engineering
In the recent years, wireless sensor networks have become prevalent in a diverse range of applications. Throughout the massive usage of wireless sensor networks, some applications require sensing and/or data collection over large areas of interest. In such applications maximizing the network lifetime thus an efficient energy consumption becomes very critical. In this paper, an improved routing protocol for large-scale WSNs based on the well-known Stable Election Protocol is proposed. With this work, the existing Stable Election Protocol is enhanced by introducing low-cost relay nodes that help to increase the lifetime and the throughput of the network. The communication between the sensor nodes and the base station is established through cluster heads and relay nodes. With the relay nodes, the simulation results show an increase in the network stability period by 34.5% and the throughput by 23%.
Citation - Scopus: 0
Max-Pivot Routing for Opportunistic Networks
(2013) Dağ, Tamer; Dağ, Tamer; Computer Engineering
Opportunistic networks are challenging types of networks where network connections are imminent. Network topologies are dynamic and can rapidly change. A path between a source node and a destination node may or may not exist the network can be disconnected. This type of behavior observed under opportunistic networks makes classical networking solutions impractical. Thus traditional routing algorithms are not suitable for such networks and will not be useful. Although flooding might be seen as the best solution to reach a destination under opportunistic networks flooding solutions' extensive usage of network resources is an extreme overhead. In this paper max- pivot routing for opportunistic networks is proposed and described. With max-pivot routing it is observed that the induced network traffic is significantly reduced while still achieving the benefits of a flooding based routing. The performance comparisons of max-pivot routing and flooding based routing methods show that max-pivot routing can be a successful routing method for opportunistic networks.
Citation - WoS: 0
Citation - Scopus: 0
Predicting User Purchases From Clickstream Data: a Comparative Analysis of Clickstream Data Representations and Machine Learning Models
(IEEE-Inst Electrical Electronics Engineers inc, 2025) Dağ, Tamer; Dag, Tamer; Computer Engineering
Predicting purchase events from e-commerce clickstream data is a critical challenge with significant implications for optimizing marketing strategies and enhancing customer experience. This study addresses this challenge by systematically evaluating and comparing multiple data representations - aggregated session attributes, recent user actions, and hybrid combinations - which bridges gaps in the existing literature and demonstrates the superiority of hybrid approaches. Unlike prior research, which typically focuses on single representations, our approach combines aggregated session-level summaries with granular, sequential user actions to capture both long-term and short-term behavioral patterns. Through comprehensive experimentation, we compared multiple machine learning models, including LightGBM, decision trees, gradient boosting, SVC, and logistic regression, using real-world e-commerce clickstream data. Notably, the hybrid representation with LightGBM achieved superior predictive performance, significantly outperforming alternative methods. Feature importance analysis revealed key factors influencing purchase likelihood, such as time since the last event, session duration, and product interactions. This study provides actionable insights into real-time marketing interventions by demonstrating the practical utility of hybrid data representations and efficient tree-based models. Our findings offer a scalable and interpretable framework for e-commerce platforms to enhance purchase predictions and optimize marketing strategies.
Citation - WoS: 0
Citation - Scopus: 0
Dynamic Priority Packet Scheduler With Deadline Considerations (dpd)
(INT INST Informatics & Systemics, 2010) Dağ, Tamer; Dağ, Tamer; Computer Engineering
Providing quality of service (QoS) to applications with different traffic characteristics based on their needs is an important research area for today's and tomorrow's high speed networks. Various techniques have been proposed to achieve good QoS for diverse application types. Among these techniques packet scheduling algorithms decide on how to process packets at network nodes
Citation - WoS: 12
Citation - Scopus: 20
Improving Energy-Efficiency of Wsns Through Lefca
(Sage Publications Inc, 2016) Cengiz, Korhan; Dağ, Tamer; Dağ, Tamer; Computer Engineering
Wireless sensor networks (WSNs) have become an important part of our lives as they can be used in vast application areas from disaster relief to health care. As a consequence the life span and the energy consumption of a WSN have become a challenging research area. According to the existing studies instead of using direct transmission or multihop routing clustering can significantly reduce the energy consumption of sensor nodes and can prolong the lifetime of a WSN. In this paper we propose a low energy fixed clustering algorithm (LEFCA) for WSNs. With LEFCA the clusters are constructed during the set-up phase. A sensor node which becomes a member of a cluster stays in the same cluster throughout the life span of the network. LEFCA not only improves the lifetime of the network but also decreases the energy dissipation significantly.
Citation - WoS: 0
Non-Preemptive Priority Scheduler With Multiple Thresholds for Network Routers
(Pamukkale Univ, 2018) Dağ, Tamer; Dağ, Tamer; Computer Engineering
The vast variety of applications available and being developed for computer networks have different quality of service requirements. One of the most significant ways to satisfy the needs of the applications is the packet scheduling algorithms employed by the network routers. By allocating router resources to the applications packet schedulers try to improve the quality of service needs of the applications. Thus the delays can be reduced or the reliability of the applications can be increased by reducing packet losses. Priority schedulers are able reduce the delay and losses for high priority applications. On the other hand for low priority applications they introduce the starvation problem. Low priority application packets can face excessive delays and losses. In this paper a non-preemptive priority scheduler with multiple thresholds (PRMT) is proposed. The PRMT scheduler needs only a single queue with predefined threshold levels for different priority applications. The PRMT scheduler eliminates the starvation problem of low priority applications without a significant impact on the high priority applications.
Citation - WoS: 0
Citation - Scopus: 1
Dynamic Multi Threshold Priority Packet Scheduling Algorithms
(EDP Sciences, 2015) Dağ, Tamer; Dağ, Tamer; Uzungenç, Sezer; Computer Engineering
Packet scheduling algorithms are developed in order to use shared transmission resources efficiently. Various application packets such as real and non-real time packets might have different QoS requirements and traditional scheduling algorithms might be insufficient to respond to the applications needs. In this paper two packet scheduling algorithms are proposed to overcome this problem: Dynamic multi threshold priority packet scheduling (DMTPS) and dynamic multi threshold priority with urgency packet scheduling (DMTPUS). The proposed algorithms aim to provide a better QoS level with a decrease in delay time and loss ratio for the low priority packets while still maintaining acceptable fairness towards high priority packets. To evaluate the performance of DMTPS and DMTPUS algorithms they are compared with the commonly used scheduling algorithms such as first come first served (FCFS) and fixed priority. Simulation results illustrate that the dynamic multi threshold priority packet scheduling algorithms can provide a better QoS for low priority packets without decreasing the QoS levels of high priority packets.
Dynamic Multi Threshold Priority Packet Scheduling Algorithms for Wireless Sensor Networks
(Kadir Has Üniversitesi, 2015) Uzungenç, Sezer; Dağ, Tamer; Dağ, Tamer; Computer Engineering
Kablosuz sensör ağlarında farklı türlerde özellikle gerçek zamanlı ve gerçek olmayan zamanlı paket zamanlama gereklidir. Sensörlerin enerji kullanımlarını ve iletim gecikmelerini azaltmak önemlidir. Tezimde yeni paket zamanlama algoritmalarını geliştirerek bunu kablosuz sensör ağlarına entegre etmeye çalışarak enerji kullanımını ve iletim gecikmelerini geliştirerek daha verimli yapıyorum. Tasarladığım dinamik çoklu eşik ve öncelikli paket zamanlama algoritmaları, düşük öncelikli veriler için gecikme zamanını ve veri kaybını azaltarak bunu yüksek öncelikli verilere adil bir şekilde davranarak yapıyor. Eşik algoritmaları günümüzde en çok kullanılan paket zamanlama algoritmalarıyla kıyaslanıyor. Bunlar ilk gelen ilk servis edilir algoritması ile öncelikli paket zamanlama algoritmasıdır. Simülasyon sonuçları gösteriyor ki dinamik çoklu eşik ve öncelikli paket zamanlama algoritmaları düşük öncelikli verilerin servis kalitesini arttırıyor ve bunu yüksek öncelikli verilerin servis kalitesini koruyarak yapıyor.
Low Energy Fixed Clustering Algorithm for Wireless Sensor Networks
(Kadir Has Üniversitesi, 2016) Cengiz, Korhan; Dağ, Tamer; Dağ, Tamer; Computer Engineering
Wireless sensor networks (WSNs) have become an important part of our lives as they can be used in vast application areas from disaster relief to health care. As a consequence the life span and the energy consumption of a WSN has become a challenging research area. According to the existing studies instead of using direct transmission or multi-hop routing clustering can significantly reduce the energy consumption of sensor nodes and can prolong the lifetime of a WSN. in this thesis low energy fixed clustering algorithm (LEFCA) and multihop low energy fixed clustering algorithm (M-LEFCA) are proposed for WSNs. With LEFCA the clusters are constructed during the set-up phase. A sensor node which becomes a member of a cluster stays in the same cluster throughout the life span of the network. LEFCA not only improves the lifetime of the network but also decreases the energy dissipation significantly. in addition proposed M-LEFCA uses multi-hop intra cluster communication approach. it selects optimum forward neighbor cluster heads (CHs) as relay nodes (RNs). M-LEFCA aims to reduce energy dissipation and prolong network lifetime of LEFCA by combining clustering and multi-hop routing approaches.