Search results for "Head"
showing 10 items of 1640 documents
Cowbird versus cuckoo hosts: a comparative study of learned nest defense
2005
One of the best example of coevolutionaru adaptations is that of the interactions between avian brood parasites and their hosts. Brood parasites lay their eggs in nests of other specieis and leave the job of caring for their young with the hosts. Hosts of brood parasites tend to suffer high reproductive costs as often they raise few of no young of their own, an effect of being parasitizes. For this reason, many hosts have evolved strategies that reduces the cost of parasitism.
Nb-90 - a potential PET nuclide: production and labeling of monoclonal antibodies
2012
Abstract Fast progressing immuno-PET gives reasons to develop new potential medium-long and long-lived radioisotopes. One of the promising candidates is 90Nb. It has a half-life of 14.6 h, which allows visualizing and quantifying processes with medium and slow kinetics, such as tumor accumulation of antibodies and antibodies fragments or polymers and other nanoparticles. 90Nb exhibits a high positron branching of 53% and an optimal energy of β + emission of E mean=0.35 MeV only. Consequently, efficient radionuclide production routes and NbV labeling techniques are required. 90Nb was produced by the 90Zr(p,n) 90Nb nuclear reaction on natural zirconium targets. No-carrier-added (n.c.a.) 90Nb …
Maximizing energy transfer and RES integration using dynamic thermal rating
2019
Abstract The production of electricity from wind and other renewable sources is rapidly increasing all over the world, causing significant changes in the management of electrical systems. The current structural asset is not adequate to manage this growing generation of energy. The hypothesis of construction of new power lines would mean taking into consideration economic, political and social problems. The following paper reports the experience gained by the Italian TSO, Terna S.p.A, on the use of the DTR (Dynamic Thermal Rating), which is able to dynamically calculate the real transport capacity of an overhead power line. The results obtained are encouraging as they show how it is possible…
Fusion of CNN and sparse representation for threat estimation near power lines and poles infrastructure using aerial stereo imagery
2021
Abstract Fires or electrical hazards and accidents can occur if vegetation is not controlled or cleared around overhead power lines, resulting in serious risks to people and property and significant costs to the community. There are numerous blackouts due to interfering the trees with the power transmission lines in hilly and urban areas. Power distribution companies are facing a challenge to monitor the vegetation to avoid blackouts and flash-over threats. Recently, several methods have been developed for vegetation monitoring; however, existing methods are either not accurate or could not provide better disparity map in the textureless region. Moreover, are not able to handle depth discon…
Lightweight Relay Selection in Multi-Hop Wake-Up Radio Enabled IoT Networks
2018
Wake-up Radios (WuRs) are becoming more popular in Internet of Things (IoT) networks owing to their overwhelming advantages such as low latency, high energy saving, and on-demand communication. In a multi-hop WuR-IoT network, route establishment between source and destination prior to actual data communications consumes a significant portion of energy. To reduce energy consumption and protocol overhead for route establishment, we propose a lightweight relay (LR) selection scheme, referred to as LR-WuR, where a lookup table and acknowledgment are used for next hop relay selection. We develop an analytical model to evaluate the performance of LR-WuR. Extensive simulations are performed to val…
On the de-energization of over-head low-voltage lines under high-impedance fault conditions
2018
Downed distribution conductors in overhead distribution systems, may not be a concern for equipment, but greatly challenge the safety of persons, as well as the integrity of properties. Upstream overcurrent protective devices may not be able to detect the magnitudes of fault currents resulting from these high-impedance faults. Even though protective devices capable to detect such faults have been available on the market, not all the utilities have equipped their stations with these products, likely due to the costs. In this paper, the authors formalize the problem, and propose a possible cost-effective solution for the low-voltage over-head lines with neutral wire. Such solution includes a …
5G V2V Communication With Antenna Selection Based on Context Awareness: Signaling and Performance Study
2022
Enhanced vehicle-to-everything (eV2X) communication is one of the key challenges to be addressed by the fifth generation (5G) of cellular mobile communications. In particular, eV2X includes some 5G vehicular applications targeting fully autonomous driving which require ultra-high reliability. Although vehicular communications are by default assumed between single antennas located on the roof of the transmitter and receiver vehicles, prior art has shown that there are other antenna positions more suitable for V2X communication, depending on the specific communication context. Antenna selection can be used in this case to select one specific antenna or a subset of them better suited for a cer…
Priority Enabled Grant-Free Access With Dynamic Slot Allocation for Heterogeneous mMTC Traffic in 5G NR Networks
2021
Although grant-based mechanisms have been a predominant approach for wireless access for years, the additional latency required for initial handshake message exchange and the extra control overhead for packet transmissions have stimulated the emergence of grant-free (GF) transmission. GF access provides a promising mechanism for carrying low and moderate traffic with small data and fits especially well for massive machine type communications (mMTC) applications. Despite a surge of interest in GF access, how to handle heterogeneous mMTC traffic based on GF mechanisms has not been investigated in depth. In this paper, we propose a priority enabled GF access scheme which performs dynamic slot …
Learning from Errors: Detecting ZigBee Interference in WiFi Networks
2014
In this work we show how to detect ZigBee interference on commodity WiFi cards by monitoring the reception errors, such as synchronization errors, invalid header formats, too long frames, etc., caused by ZigBee transmissions. Indeed, in presence of non-WiFi modulated signals, the occurrence of these types of errors follows statistics that can be easily recognized. Moreover, the duration of the error bursts depends on the transmission interval of the interference source, while the error spacing depends on the receiver implementation. On the basis of these considerations, we propose the adoption of hidden Markov chains for characterizing the behavior of WiFi receivers in presence of controlle…
The Effectiveness of LDOCE Definitions for Concrete and Abstract Nouns in Headword- and Picture-Identification Tasks
2021
Abstract LDOCE uses a defining vocabulary to make their definitions intelligible to the user. Critics claim this policy may result in imprecise definitions, something especially noticeable in certain concrete and abstract words that are difficult to define by a definition only. This paper examines to what extent LDOCE definitions of such words help learners identify the objects and words being defined. In our experiment on 381 learners of English as a foreign language, three groups of participants viewed different definition types: simplified definitions of LDOCE, unsimplified definitions of MWC, and definitions written in the learners’ mother tongue (UDPL/TR). The results show that the LDO…