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Real time locating systems (RTLS) determine and track the location of assets and person using active tags. Two or more readers can estimate the tag's range from each reader and determine its location. In order to determine tag's location, there are several methods. This paper presents a real time locating system which is based on time difference of(More)
— Logistics has grown dramatically, especially where identifying, locating, or tracking objects in ports are important, because ports are gateways to extended markets. In this paper, we analyze the new requirements of port logistics after a brief introduction and present a system prototype. conservation of energy to extend the live of the tags for as long(More)
Real time locating systems (RTLS) are required to provide high quality service for port logistics. When such locating systems are applied to port logistics, however, they encounter the problem of unreachable signals. The environments of port logistics have radio-shaded areas (RSA), which often cause failures in measurement or positioning errors. This paper(More)
RTLS (Real Time Locating Systems) are used to track the location of an object or person in real time. However, if there are many tags and readers, the conventional centralized RTLS server with a single location engine may fail to estimate the location of the tags. Furthermore, if the server does not receive a tag’s signal due to pass loss or none(More)
As the era of ubiquitous computing approaches, there is a growing need for a reliable, efficient positioning and tracking system. Localization involves continuous determination and tracking of the location of assets and personnel. Localization using time difference of arrival (TDOA) involves determining the location of a tag by calculating the time(More)
In wireless sensor networks, a number of nodes deployed in dense manner should be self-configured to establish the topology that provides communication and sensing coverage under stringent energy constraints. To establish an efficient topology, we propose the TRaffic-Aware Topology control (TRAT) algorithm that reduces energy consumption by considering the(More)
To overcome a world-wide water shortage problem, numerous desalination methods have been developed with state-of-the-art power efficiency. Here we propose a spontaneous desalting mechanism referred to as the capillarity ion concentration polarization. An ion-depletion zone is spontaneously formed near a nanoporous material by the permselective ion(More)