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Yayın Force-directed approaches to sensor localization(SIAM, 2006) Efrat, Alon; Forrester, David; Iyer, Anand; Kobourov, Stephen G.; Erten, CesimWe consider the centralized, anchor-free sensor localization problem. We consider the case where the sensor network reports range information and the case where in addition to the range, we also have angular information about the relative order of each sensor's neighbors. We experimented with classic and new force-directed techniques. The classic techniques work well for small networks with nodes distributed in simple regions. However, these techniques do not scale well with network size and yield poor results with noisy data. We describe a new force-directed technique, based on a multi-scale dead-reckoning, that scales well for large networks, is resilient under range errors, and can reconstruct complex underlying regions.Yayın A robust localization framework to handle noisy measurements in wireless sensor networks(IEEE, 2009-09-14) Erten, Cesim; Karataş, ÖmerWe construct a robust localization framework to handle noisy measurements in wireless sensor networks. Traditionally many approaches employ the distance information gathered from ranging devices of the sensor nodes to achieve localization. However the measurements of these devices may contain noise both as hardware noise and as environmental noise due to the employment conditions of the network. It Is necessary to provide a general framework that handles such a noise in data and yet still be applicable within several localization algorithms. In order to handle noise in distance measurements, our framework utilizes convex constraints and confidence intervals of a random variable. At the end of the localization process nodes are assigned to a set of feasible regions with corresponding probabilities. The accuracy of the localization can be adjusted and the framework can easily be embedded to work within previously suggested localization algorithms.Yayın Design and implementation of a smart beehive and its monitoring system using microservices in the context of IoT and open data(Elsevier B.V., 2022-05) Aydın, Şahin; Aydın, Mehmet NafizIt is essential to keep honey bees healthy for providing a sustainable ecological balance. One way of keeping honey bees healthy is to be able to monitor and control the general conditions in a beehive and also outside of a beehive. Monitoring systems offer an effective way of accessing, visualizing, sharing, and managing data that is gathered from performed agricultural and livestock activities for domain stakeholders. Such systems have recently been implemented based on wireless sensor networks (WSN) and IoT to monitor the activities of honey bees in beehives as well. Scholars have shown considerable interests in proposing IoT- and WSN-based beehive monitoring systems, but much of the research up to now lacks in proposing appropriate architecture for open data driven beehive monitoring systems. Developing a robust monitoring system based on a contemporary software architecture such as microservices can be of great help to be able to control the activities of honey bees and more importantly to be able to keep them healthy in beehives. This research sets out to design and implementation of a sustainable WSN-based beehive monitoring platform using a microservice architecture. We pointed out that by adopting microservices one can deal with long-standing problems with heterogeneity, interoperability, scalability, agility, reliability, maintainability issues, and in turn achieve sustainable WSN-based beehive monitoring systems.Yayın Improving age of information in random access channels(Institute of Electrical and Electronics Engineers Inc., 2020-07) Atabay, Doğa Can; Uysal, Elif; Kaya, OnurWe study Age of Information (AoI) in a random access channel where a number of devices try to send status updates over a common medium. Assuming a time-slotted scenario where multiple transmissions result in collision, we propose a threshold-based lazy version of Slotted ALOHA and derive the time average AoI achieved by this policy. We demonstrate that the average AoI performance of the lazy policy is significantly better than Slotted ALOHA, and close to the ideal round robin benchmark.Yayın When to pull data for minimum age penalty(IEEE, 2021-10-18) Yavaşcan, Orhan Tahir; Ceran, Elif Tuğçe; Cakir, Zeynep; Uysal, Elif; Kaya, OnurA communication receiver that wants to pull data from a remote sensor by exploiting wireless energy transfer is considered. The receiver has a long-term average energy budget for this operation, and its goal is to keep the time average of a general age penalty function as small as possible. The channel from the source to the receiver is a two-state (ON/OFF) communication link whose state is IID or Markovian, and known instantaneously by the receiver. Modeling the problem as a constrained Markov decision problem, we obtain a randomized threshold-based decision policy that achieves the minimum possible average age penalty. We determine the optimal time average Age of Information and age violation probabilities by exploiting the optimality of the derived policy.Yayın Medium access control and routing in industrial wireless sensor networks(CRC Press, 2017-01-01) Tüysüz Erman, Ayşegül; Durmaz İncel, ÖzlemWireless Sensor Networks (WSNs) appear as a promising solution for industrial applications, especially for monitoring purposes, due to the advantages that they provide [19]. First of all, they overcome the wiring constraints present in wired industrial monitoring and control systems. Other advantages can be listed as ease of installation and maintenance, reduced cost, and better performance [50]. On the other hand, lack of standardization, strict real-timeliness, and reliability requirements of some industrial applications have limited their use in industrial domains [6]. Today, however, initial examples of industrial wireless sensor networks (IWSNs) do appear especially on process monitoring and control [28, 19], supported with standardization efforts such as IEEE 802.15.4 [2], WirelessHART [40], and ISA100.11a [25].Yayın Resource allocation in the finite blocklength regime under PAoI and delay violation constraints(IEEE, 2023-08-27) Kartal, Özkan Tuğberk; Kaya, Onur; Uysal, ElifURLLC (Ultra-reliable low-latency communication) is one of the more challenging modes for 5G for resource allocation (RA). Most of the previous studies for RA for wireless access in URLLC assumed known packet arrival processes, and focused on maximizing average rates or throughput. The objective of this paper is to present a formulation of allocating resource blocks, modulation and coding rates to multiple short packet machine-type information flows to provide information age and delay violation guarantees. The scenario is motivated by the scheduling of URLLC flows among users served by a common 5G base station. The problem involves the selections of frequency allocation policy and modulation and coding scheme (MCS) under estimated CSI. Moreover, the sensitivity of the information packet size on the choice of modulation and coding parameters as well as the number of resource blocks and the choice of the number of pilot symbols is demonstrated. The results of this formulation are compared with resource allocation algorithms in the literature.
