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

Full item page

Scholarly Output

41

Articles

10

Citation Count

0

Supervised Theses

11 Scholarly Output Search Results

Now showing 1 - 10 of 41

Max-Pivot Routing for Opportunistic Networks
(2013) Dağ, Tamer
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.
Non-Preemptive Priority Scheduler With Multiple Thresholds for Network Routers
(Pamukkale Univ, 2018) Dağ, Tamer
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.
An Improved Hybrid Stable Election Routing Protocol for Large Scale Wsns
(IEEE, 2021) Hamad, Lana I. S.; Dag, Tamer; Gucluoglu, Tansal
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%.
Dynamic Priority Packet Scheduler With Deadline Considerations (dpd)
(INT INST Informatics & Systemics, 2010) Dağ, Tamer
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
Increasing Energy Efficiency of Wsns Through Optimization of Mobile Base Station Locations
(IEEE, 2021) Abbas, Sahar S. A.; Dag, Tamer; Gucluoglu, Tansal
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.
Improving Energy-Efficiency of Wsns Through Lefca
(Sage Publications Inc, 2016) Cengiz, Korhan; Dağ, Tamer
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.
Location-Allocation Through Machine Learning for E-Commerce Logistic Services
(Kadir Has Üniversitesi, 2022) TOPUZ, TAYYİP; Tamer Dağ
Companies desire to expand their businesses in such a way that there will not be any loss in their revenues. An e-commerce logistics company functions as the distribution and delivery of goods to buyers. To expand the business, opening new branches is a critical decision since determining the location of a branch correctly will not only help an e commerce logistics company to increase its revenue but also improve customer satisfaction. The logistic network, which is based on locations, is the most vital input for their business. For such decisions, data science is becoming an essential tool in recent years. Research shows that demographic information has a considerable impact on consumer behavior in e-commerce. In this thesis, the demand potential is studied by using demographic data and current demand for an e-commerce logistics company. The outcome of this work can be used to determine the location of new branches. Machine learning techniques are being used to decide the location of a new branch with the help of delivery demand potential prediction.
Extending the Lifetime of Wsns With Maximum Energy Selection Algorithm (mesa)
(Institute of Electrical and Electronics Engineers Inc., 2017) Cengiz, Korhan; Dağ, Tamer
The limited battery supply of a sensor node is one of the most important factors that limit the lifetime of the WSNs. As a consequence increasing the lifetime of WSNs through energy efficient mechanisms has become a challenging research area. Previous studies have shown that instead of implementing direct transmission or multi-hop routing clustering can significantly improve the total energy dissipation and lifetime of a WSN. The traditional LEACH and LEACH based algorithms have evolved from this idea. In this paper we propose a fixed clustering routing algorithm for WSNs which selects the node with maximum residual energy for the following rounds according to a threshold level. The Maximum Energy Selection Algorithm (MESA) can improve the lifetime of the network and reduce the energy dissipation significantly. Our studies have shown that when compared with LEACH and LEACH based algorithms such as ModLEACH and DEEC MESA gains for the lifetime extension and energy dissipation is very important. © 2016 IEEE.
Using Machine Learning Classifiers To Identify the Critical Proteins in Down Syndrome
(Association for Computing Machinery, 2018) Kulan, Handan; Dağ, Tamer
Pharmacotherapies of intellectual disability (ID) are largely unknown as the abnormalities at the complex molecular level which causes ID are difficult to understand. Down syndrome (DS) which is the prevalent cause of ID and caused by an extra copy of the human chromosome21 (Hsa21) has been investigated on protein levels by using the Ts65Dn mouse model of DS which are orthologs of %50 of Hsa21 classical protein coding genes. Recent works have applied the classification methods to understand critical factors in DS as it is believed that the problem was naturally related to classification problem since the determination of proteins discriminatory between classes of mice was required. In this study we apply forward feature selection method to identify correlated proteins and their interactions in DS. After identification we report supervised learning model of expression levels of selected proteins in order to understand the critical proteins for diagnosing and explaining DS. The proposed technique depicts optimum classification results achieved by optimizing parameters with grid search. When compared with the former work our classification results give higher accuracy. © 2018 Association for Computing Machinery.
An Energy Efficient Routing Algorithm (x-Centric Routing) for Sensor Networks
(INT INST Informatics & Systemics, 2011) Ataç, Göktuğ; Dağ, Tamer
Recent developments in wireless communications and electronics technologies have enabled the progress in low cost sensor networks. Sensor networks differ from traditional networks in several ways such as the severe energy constraints redundant low-rate date and many-to-one flows that the sensor networks require. One of the major challenges facing the design of a routing protocol for Wireless Sensor Networks (WSNs) is to find the most reliable path between the sources and the sink node by considering the energy awareness as an essential design parameter. This paper introduces a new routing protocol called as X-Centric routing by considering the above parameters. Under the X-Centric routing the decision making mechanism depends on the capacity of the sink node by switching between address-centric routing (AC-Routing) and data-centric routing (DC-Routing). The design tradeoffs between energy and communication overhead savings in these routing algorithms have been considered by considering the advantages and performance issues of each routing algorithm.