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

Investigation the risk of autism by evaluating prenatal and postnatal exposure to traffic-related air pollution
(Kadir Has Üniversitesi, 2020) Dağ, Tamer; Dağ, Tamer
Autism spectrum disorder (ASD ) which is a group of neurodevelopmental disorder that appears during the first few years of a child's life affecting a child's communication and socialization abilities with increasing prevalence. Recently, several recent studies have found associations between exposure to traffic-related air pollution (TRAP) and ASD. The primary aim of this study is to investigate/examine the relation between TRAP and four air pollutants (NO2, O3, PM10, PM2.5) and ASD during prenatal or post-natal by using multiple logistic regression models and variable selection methods. Results show that the adjusted odds ratio (AOR) for ASD per IQR increase was strongly associated for exposure to NO2 during the first year period, was moderately associated for exposure to NO2 (from interstate highways during the third trimester; from the county highway during the first year; from city street during the first year; from all roads during the all pregnancy; from all roads during the first trimester) and O3 during the second year, and weakly associated with exposure to NO2 from interstate highways during the second trimester, O3 during the first trimester and PM2.5 during the second year. Additionally, comparing fourth to first quartile exposures the AOR was 15.47 for NO2 from interstate highways during the third trimester, was 5.00 for NO2 from all roads during the first trimester, and comparing third to first quartile exposures the AOR was 2.31 for PM2.5 during the second year. As a result, a strong relationship between NO2 exposure and ASD was detected for each 7.1 ppb [IQR] increase in NO2 during the first year and subjects exposed to a higher level of NO2 during the first and third trimester, and PM2.5 during the second year was also associated with increased risk of ASD.
Citation Count: 2
Performance Improvement of Threshold Based Audio Steganography Using Parallel Computation
(Science & Information SAI Organization Ltd, 2016) Dağ, Tamer; Shehzad, Danish; Umar, Arif Iqbal; Khan, Zakir; Dağ, Tamer; Ul Amin, Noor
Audio steganography is used to hide secret information inside audio signal for the secure and reliable transfer of information. Various steganography techniques have been proposed and implemented to ensure adequate security level. The existing techniques either focus on the payload or security but none of them has ensured both security and payload at same time. Data Dependency in existing solution was reluctant for the execution of steganography mechanism serially. The audio data and secret data pre-processing were done and existing techniques were experimentally tested in Matlab that ensured the existence of problem in efficient execution. The efficient least significant bit steganography scheme removed the pipelining hazard and calculated Steganography parallel on distributed memory systems. This scheme ensures security focuses on payload along with provisioning of efficient solution. The result depicts that it not only ensures adequate security level but also provides better and efficient solution.
Citation Count: 0
An Improved Hybrid Stable Election Routing Protocol for Large Scale WSNs
(IEEE, 2021) Dağ, Tamer; 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%.
Citation Count: 0
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.
Location-allocation through machine learning for e-commerce logistic services
(Kadir Has Üniversitesi, 2022) Dağ, Tamer; 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.
Citation Count: 0
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
Citation Count: 0
Increasing Energy Efficiency of WSNs Through Optimization of Mobile Base Station Locations
(IEEE, 2021) Dağ, Tamer; 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.
Citation Count: 0
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.
Citation Count: 12
Improving Energy-Efficiency of WSNs through LEFCA
(Sage Publications Inc, 2016) Dağ, Tamer; 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.
Citation Count: 13
Low Energy Fixed Clustering Algorithm (LEFCA) for Wireless Sensor Networks
(IEEE, 2015) Dağ, Tamer; 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 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 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 and increases the throughput significantly.