Papuk Nature Park, unlike most similar parks and preserves in the world, contains active quarries. Quarries dig stone from the ground, creating dust and exposing deeper, potentially more radioactive ...layers. Since the forest trails in the Park lead right up to the quarries, we believed it was important to determine the radiological impact of the quarries on the Park environment. We measured ambient dose rate equivalent
(10) and sampled moss at 26 Park locations along two of four quarries, along the road between them, and near Lake Orahovac, a very popular tourist destination close to the quarries. Moss is a standard bioindicator of exposure to heavy metals, including radionuclides. Using-gamma ray spectrometry we determined the activity concentration of
Cs and of representative naturally occurring radionuclides –
U,
Ra,
Pb,
Th, and
K – in sampled moss.
(10) at selected locations was similar to the background
(10) measured continuously all over Croatia. The ranges of measured activity concentrations of
Cs and naturally occurring radionuclides in moss did not differ significantly from other parts of Croatia and nearby countries.
O texto aqui apresentado é um recorte da pesquisa de mestrado defendida em 2016 na Universidade Nova de Lisboa, em que se investigou os aspectos educativos do estudo em grupo da filosofia dos Doze ...Passos nas salas de Alcoólicos Anônimos – AA – nos contextos brasileiro e português, enfatizando as estratégias de educação em saúde e a educação do sujeito. Optou-se por focalizar, neste artigo, a articulação entre o estudo dos Doze Passos e os subsídios teóricos de Feuerstein (1980), Dewey (1959), Freire (1996) e Makarenko (1975). Os resultados desse estudo apontaram não só para o valor do conteúdo do texto dos referidos passos, mas especialmente, para o modo de trabalhá-los, lançando um olhar atento aos sujeitos implicados no processo. Questões referentes ao valor das narrativas, ao não protagonismo dos que conduzem o estudo, à auto-gestão e à autonomia ficaram patentes, sinalizando, dessa forma, contribuições valiosas para todos aqueles que transitam em cenários educativos diversos.
•The state of the art of PON energy saving is discussed.•The lattice theory and fixed point are used to solve the sleep and doze duration time.•We examined the QoS performance based on different ...simulation scenarios.•We compared our results with the architecture without energy-saving mechanism.
Time-division multiplexing passive optical network (TDM-PON) is referred to as a green network because it consumes minimum energy compared to the other access networks technologies. The optical network unit (ONU) mainly chooses to adjust energy-saving in TDM-PON by turning off its receiver and/or transmitter for the substantial time that is called doze or sleep mode respectively. The main challenge in the TDM-PON energy-saving is finding acceptable sleep/doze duration time to achieve energy-saving and guarantee the quality of service (QoS). This paper proposes a mathematical model built based on the lattice theory, which is applied to the results of the fixed-point theory. In the domain of nonlinear systems, each monotone function on a chosen complete lattice has a fixed point, and this point can be interpreted as the solution of the system. The output of the mathematical model is the sleep/doze duration domain that satisfies all requirements and guarantees the QoS metrics. The mathematical model is adopted with doze mode conditions to evaluate the system. Simulation results approve our model that achieves energy-saving up to 63% while keeping the QoS parameters in the acceptable boundary.
A guerra dos camponeses alemães, que durou de 1524 a 1525, foi conhecida como ‘o maior evento natural da história do Estado Alemão’ (Leopond von Ranke). Desde pelo menos o século XVIII as guerras ...camponesas na Alemanha produziram uma vasta bibliografia com diferentes interpretações. Este pequeno ensaio analisa as tendências da historiografia atual sobre o assunto e traz uma proposta de tradução dos famosos 12 artigos dos camponeses da Suábia Superior, considerados um dos mais importantes documentos dos direitos humanos e das liberdades civis após a queda do império romano.
This paper aims to explore the potential of a high spectrum efficiency (SE) technology, coordinated multi-point (CoMP) transmission, for improving energy efficiency (EE) of downlink cellular ...networks. To this end, a traffic-aware mechanism, named cooperative base station (BS) doze, is introduced and optimized. The key idea is to allow BS idling by exploiting the delay tolerance of some users as well as the short-term spatio-temporal traffic fluctuations in the network, and to increase the opportunity of the idling by using CoMP transmission. The cooperative BS doze strategy involves BS time-slot doze pattern, and multicell user scheduling and cooperative precoding with different amount of data sharing, which are jointly optimized in a unified framework. To ensure various performance requirements of multiple users including delay tolerance and data rate, we maximize the network EE under different time-average rate constraints for different users, where the consumptions on transmit power, circuitry power and backhauling power are taken into account. We then propose a hierarchical iterative algorithm to solve the optimization problem. Simulations under practical power consumption parameters demonstrate that cooperative BS doze can provide substantial EE gain and support high data rate services with high achievable SE.
•We designed a new two-stage energy-saving mechanism for doze mode in EPON.•The doze sleep duration is extended for longer time with acceptable QoS.•We examined the QoS performance based on different ...simulation scenarios.•We compared our results with the architecture without energy-saving mechanism.
Sleep and doze power-saving modes are the common ways to reduce power consumption of optical network units (ONUs) in Ethernet passive optical network (EPON). The doze mode turns off the ONU transmitter when there is no traffic in the upstream direction while the sleep mode turns off the ONU transmitter and receiver. As the result, the sleep mode is more efficient compared to the doze mode, but it introduces additional complexity of scheduling and signaling, losses the clock synchronization and requires long clock recovery time; furthermore, it requires the cooperation of the optical line terminal (OLT) in the downstream direction to queue frames. To improve the energy-saving in the doze mode, a new two-stage mechanism is introduced that the doze sleep duration is extended for longer time with acceptable quality-of-services (QoS) metrics when ONU is idle in the current cycle. By this way the ONU enters the doze mode even in the high load traffic; moreover, the green dynamic bandwidth allocation (GBA) is proposed to calculate the doze sleep duration based on the ONU queue state and incoming traffic ratio. Simulation results show that the proposed mechanism significantly improves the energy-saving 74% and 54% when traffic load is from the light load to the high load in different traffic situations, and also promises the QoS performance.
Current networking equipment usually provides several energy profiles with different performance capabilities. For example, in EPON systems, ONUs are able to switch their transmitters off when there ...is no data to transmit. This low power mode, known as doze mode, can significantly reduce power consumption in EPONs if wisely used. In this paper, we evaluate through simulation the potential power savings that can be obtained using this mode in many different scenarios. In particular, we analyze the impact of the DBA algorithm and the mode governor on both energy efficiency and frame delay with different implementations of the doze mode.
An Ethernet passive optical network (EPON) is an optical access network that allows a higher data rate with low power consumption. To improve energy savings for an EPON, the sleep and doze modes for ...the optical network units (ONUs) play a pivotal role. Many prediction schemes have been proposed to control these modes. To increase the prediction accuracy, this study proposes an energy-efficient approach that uses a support vector regression (SVR) model. A dynamic bandwidth allocation (DBA) scheme called SVR-DBA is designed to allocate bandwidth to ONUs more efficiently and fairly. To determine the effectiveness of the proposed scheme, simulations are performed. The simulation results show that the proposed scheme decreases energy consumption for ONUs by up to 47% and fulfills the quality-of-service (QoS) requirements in terms of delay, jitter, and packet loss.
PDF
