Hayrettin Evirgen

Bio: Hayrettin Evirgen is an academic researcher from Sakarya University. The author has contributed to research in topics: Communications system & Change data capture. The author has an hindex of 4, co-authored 11 publications receiving 65 citations. Previous affiliations of Hayrettin Evirgen include Istanbul University.

A Survey on LoRaWAN Architecture, Protocol and Technologies

Abstract: Internet of Things (IoT) expansion led the market to find alternative communication technologies since existing protocols are insufficient in terms of coverage, energy consumption to fit IoT needs. Low Power Wide Area Networks (LPWAN) emerged as an alternative cost-effective communication technology for the IoT market. LoRaWAN is an open LPWAN standard developed by LoRa Alliance and has key features i.e., low energy consumption, long-range communication, builtin security, GPS-free positioning. In this paper, we will introduce LoRaWAN technology, the state of art studies in the literature and provide open opportunities.

Prediction and Diagnosis of Diabetic Retinopathy using Data Mining Technique

Abstract: Diabetic retinopathy is the most common form of eye problem affecting people with diabetes, usually only affects people who have had diabetes for a long time period and can result in blindness The aim of this study is to examine the naive Bayes algorithm which is one of the classification methods in data mining, and to analyze real life dataset in order to built predictive system for diabetic retinopathy disease A total of 385 diabetes patients’ data were used to train the prediction system All the categorical features in the dataset were selected by doctors and evaluation was made based on these features The dataset was obtained at the Eye Clinic of the Sakarya University Educational and Research Hospital It has been proven with cross-validation that naive Bayes algorithm can be used for diabetic retinopathy prediction with an improved accuracy of 89% Keywords: Naive Bayes, Diabetic Retinopathy, Data Mining

Determination of Critical Achievement Factors in Distance Education by Using Structural Equality Model: A Case Study of E-MBA Program Held in Sakarya University

Abstract: Nowadays, distance learning education has been started to become familiar in behalf of classical face to face education (F2F) model. Web based learning is a major part of distance education systems. Web based distance learning can be defined shortly as an education type which doesn’t force students and educators being into the same mediums. This education model has a student-cantered structure. In this type of education students can learn given lectures without dependency of time and place. And also students can communicate with their educators via various technology platforms. This is a fact that there are many factors have been effecting achievement of students in web-based distance learning. The success of students can be increased while determining weighted achievement factors. This study aims for determining critical achievement factors in a case study of e-mba distance education program held Sakarya University, by using structural equation model.

Evolution of the Current Telecommunications Networks and the Next Generation Optical Networks

Abstract: During the years between 1995 and 2000, there had been a strong competition between IP and ATM. MPLS that was approved by IETF in 1997, seems to end this competition with combination of best features of IP and ATM. MPLmS that is the equivalent of MPLS in optical networks, was designed in 1999. Afterwards, a new version of MPLmS, that is to say GMPLS, was developed in 2000 by IETF. Routing and signalling protocols that are supported by MPLS were extended to support GMPLS. The broadband boom, specifically growing data demand in high speed, and increasing bandwidth requirements has caused the evolution of the current transport networks. As a consequence, the IP over WDM networks, that integrate the traditional WDM networks having bandwidths of terabits and IP networks on which all applications run, has been developed. This article contains information on the MPLS, MPLmS and GMPLS network architectures which started to work on network backbones as a result of the evolution of telecommunications networks and new generation IP over WDM networks.

Evolution of multiprotocol label switching

Abstract: Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates.

LoRaFarM: A LoRaWAN-Based Smart Farming Modular IoT Architecture.

Abstract: Presently, the adoption of Internet of Things (IoT)-related technologies in the Smart Farming domain is rapidly emerging. The ultimate goal is to collect, monitor, and effectively employ relevant data for agricultural processes, with the purpose of achieving an optimized and more environmentally sustainable agriculture. In this paper, a low-cost, modular, and Long-Range Wide-Area Network (LoRaWAN)-based IoT platform, denoted as "LoRaWAN-based Smart Farming Modular IoT Architecture" (LoRaFarM), and aimed at improving the management of generic farms in a highly customizable way, is presented. The platform, built around a core middleware, is easily extensible with ad-hoc low-level modules (feeding the middleware with data coming from the sensors deployed in the farm) or high-level modules (providing advanced functionalities to the farmer). The proposed platform has been evaluated in a real farm in Italy, collecting environmental data (air/soil temperature and humidity) related to the growth of farm products (namely grapes and greenhouse vegetables) over a period of three months. A web-based visualization tool for the collected data is also presented, to validate the LoRaFarM architecture.

A Survey on Adaptive Data Rate Optimization in LoRaWAN: Recent Solutions and Major Challenges.

Abstract: Long-Range Wide Area Network (LoRaWAN) is a fast-growing communication system for Low Power Wide Area Networks (LPWAN) in the Internet of Things (IoTs) deployments. LoRaWAN is built to optimize LPWANs for battery lifetime, capacity, range, and cost. LoRaWAN employs an Adaptive Data Rate (ADR) scheme that dynamically optimizes data rate, airtime, and energy consumption. The major challenge in LoRaWAN is that the LoRa specification does not state how the network server must command end nodes pertaining rate adaptation. As a result, numerous ADR schemes have been proposed to cater for the many applications of IoT technology, the quality of service requirements, different metrics, and radio frequency (RF) conditions. This offers a challenge for the reliability and suitability of these schemes. This paper presents a comprehensive review of the research on ADR algorithms for LoRaWAN technology. First, we provide an overview of LoRaWAN network performance that has been explored and documented in the literature and then focus on recent solutions for ADR as an optimization approach to improve throughput, energy efficiency and scalability. We then distinguish the approaches used, highlight their strengths and drawbacks, and provide a comparison of these approaches. Finally, we identify some research gaps and future directions.

Design and Analysis of Optical Flow-Switched Networks

Abstract: In our previous work [Chan, ldquoOptical flow switching,rdquo in BROADNETS 2006, pp. 1-8; Weichenberg, ldquoCost-efficient optical network architectures,rdquo in ECOC 2006, pp. 1-2; Weichenberg, ldquoOn the throughput-cost tradeoff of multi-tiered optical network architectures,rdquo GLOBECOM '06, pp. 1-6], we presented optical flow switching (OFS) as a key enabler of scalable future optical networks. We now address the design and analysis of OFS networks in a more comprehensive fashion. The contributions of this work, in particular, are in providing partial answers to the questions of how OFS networks can be implemented, how well they perform, and how their economics compare with those of other architectures. With respect to implementation, we present a sensible scheduling algorithm for inter-metropolitan-area-network (inter-MAN) OFS communication. Our performance study builds upon our work in IEEE J. Sel. Areas Commun., vol. 25, no. 6, pp. 84-101, 2007 and Weichenberg, ldquoPerformance analysis of optical flow switching,rdquo presented at the IEEE International Conference on Communications, Dresden, Germany, June 14-18, 2009, and includes a comparative capacity analysis for the wide area, as well as an analytical approximation of the throughput-delay trade-off offered by OFS for inter-MAN communication. Last, with regard to the economics of OFS, we extend our previous work from ECOC 2006 and GLOBECOM '06 in carrying out an optimized throughput-cost comparison of OFS with other prominent candidate architectures. Our conclusions indicate that OFS offers a significant advantage over other architectures in economic scalability. In particular, for sufficiently heavy traffic, OFS handles large transactions at far lower cost than other optical network architectures. In light of the increasing importance of large transactions to communication networks, we conclude that OFS may be crucial to the future viability of optical networking.

LoRaWAN Mesh Networks: A Review and Classification of Multihop Communication.

Abstract: The growth of the Internet of Things (IoT) led to the deployment of many applications that use wireless networks, like smart cities and smart agriculture. Low Power Wide Area Networks (LPWANs) meet many requirements of IoT, such as energy efficiency, low cost, large coverage area, and large-scale deployment. Long Range Wide Area Network (LoRaWAN) networks are one of the most studied and implemented LPWAN technologies, due to the facility to build private networks with an open standard. Typical LoRaWAN networks are single-hop in a star topology, composed of end-devices that transmit data directly to gateways. Recently, several studies proposed multihop LoRaWAN networks, thus forming wireless mesh networks. This article provides a review of the state-of-the-art multihop proposals for LoRaWAN. In addition, we carried out a comparative analysis and classification, considering technical characteristics, intermediate devices function, and network topologies. This paper also discusses open issues and future directions to realize the full potential of multihop networking. We hope to encourage other researchers to work on improving the performance of LoRaWAN mesh networks, with more theoretical and simulation analysis, as well as practical deployments.