Comparison between power line communication multipath model and coaxial cable interferometer theory

The authors have studied a new method to find parameters of broadband power line communication channel model. Lossless power line communication channel model is compared with classical interferometers approach to develop this model. The authors also used coaxial cables to simulate a multipath channel, because it can behave like a lossless power line communication channel. Thus, measurements were carried out with a network analyzer to find S parameters. The modeling parameters, for the multipath model were found after using MATLAB software and classical interferometers approach. Then, theoretical and experimental results are presented and compared. Copyright © 2012 John Wiley & Sons, Ltd.     

Systemic Diagramming: An Approach to Decoding Urban Ecologies

For many students, sustainability has become an obligatory add-on for any project. Here Ulysses Sengupta and Deljana Iossifova explain how they have sought to address this in their teaching at the University of Nottingham through a ‘systemic diagramming’ approach. This provides essential tools for understanding how resource flows and environmental concerns are embedded in physical urban transformation, socioeconomic fault lines and underlying power relations.     

Measurement of the Energy Spectrum of the Neutrons inside the Neutron Flux Trap Assembled in the Center of the Reactor Core IPEN/MB-01

This paper presents the neutron energy spectrum in the central position of a neutron flux trap assembled in the core center of the research nuclear reactor IPEN/MB-01, obtained by an unfolding method. To this end, we have used several different types of activation foils （Au, Sc, Ti, Ni, and plates） which have been irradiated in the central position of the reactor core （setting number 203） at a reactor power level （64.57±2.91 watts）. The activation foils were counted by solid-state detector HPGe （high pure germanium detector） （gamma spectrometry）. The experimental data of nuclear reaction rates （saturated activity per target nucleus） and a neutron spectrum estimated by a reactor physics computer code are the main input data to get the most suitable neutron spectrum in the irradiation position obtained through SANDBP （spectrum analysis neutron detection code-version Budapest University） code： a neutron spectra unfolding code that uses an iterative adjustment method. the integral neutron flux, （2.41 ± 0.01） × 10^9 n·cm^-2·s^-1 for the thermal The adjustment resulted in （3.85 ± 0.14） × 10^9 n·cm^-2·s^-1 for neutron flux, （1.09 ±0.02） × 10^9n·cm^-2·s^-1 for intermediate neutron flux and （3.41 ± 0.02） × 10^8 n·cm^-2·s^-1 for the fast neutrons flux. These results can be used to verify and validate the nuclear reactor codes and its associated nuclear data libraries, besides, show how much effective it can be that the use of a neutron flux trap in the nuclear reactor core to increase the thermal neutron flux without increase the operation reactor power level. The thermal neutral flux increased 4.04 ± 0.21 times compared with the standard configuration of the reactor core.     

An artificial moth: Chemical source localization using a robot based neuronal model of moth optomotor anemotactic search

Robots have been used to model nature, while nature in turn can contribute to the real-world artifacts we construct. One particular domain of interest is chemical search where a number of efforts are underway to construct mobile chemical search and localization systems. We report on a project that aims at constructing such a system based on our understanding of the pheromone communication system of the moth. Based on an overview of the peripheral processing of chemical cues by the moth and its role in the organization of behavior we emphasize the multimodal aspects of chemical search, i.e. optomotor anemotactic chemical search. We present a model of this behavior that we test in combination with a novel thin metal oxide sensor and custom build mobile robots. We show that the sensor is able to detect the odor cue, ethanol, under varying flow conditions. Subsequently we show that the standard model of insect chemical search, consisting of a surge and cast phases, provides for robust search and localization performance. The same holds when it is augmented with an optomotor collision avoidance model based on the Lobula Giant Movement Detector (LGMD) neuron of the locust. We compare our results to others who have used the moth as inspiration for the construction of odor robots.     

Citation behavior in popular scientific papers: what is behind obscure citations? The case of ethnobotany

Citation studies have become an important tool for understanding scientific communication processes, as they enable the identification of several characteristics of information-retrieval behavior. This study seeks to analyze citation behavior using two popular ethnobotany articles, and our analysis is guided by the following question: when an author references a work, is he pointing out the work??s theoretical contribution, or is bias a factor in citing this reference? Citation analysis reveals an interesting phenomenon, as the majority of citing texts do not consider the theoretical contributions made by the articles cited. Two possible conclusions can be drawn from this scenario: (1) citing authors read the original texts that they cite only superficially, and (2) the works cited are not read by the vast majority of people who reference them. Thus, it is clear that even with sufficient access to reference texts; ethnobotanical studies highlight elements less relevant to the research and reproduce discussions in a non-reflective manner.     

Assessing snowmelt dynamics with NASA scatterometer (NSCAT) data and a hydrologic process model

The presence of snow strongly impacts the exchange of moisture and energy between the land surface and atmosphere. In the interior of the northern hemisphere continents, snowmelt on frozen soils can cause or exacerbate major floods. Microwave remote sensing from satellite platforms has the potential to monitor the freeze-thaw status of soil and overlying snow packs over large areas. We evaluate the backscatter response of the NSCAT scatterometer to changing snow surface conditions, especially freeze and thaw status, using a macroscale hydrology model and the NSCAT backscatter data for the upper Mississippi River basin of the north central U.S. and the Boreal Ecosystem Atmosphere Study (BOREAS) region in central Canada. We compared the snowmelt conditions simulated by the Variable Infiltration Capacity (VIC) macroscale hydrology model driven with surface meteorological observations with NSCAT measurements for 1996-1997 snow season. A mid-winter thaw event (in February) and late season melt (April-May) are evaluated for both regions. Comparison of backscatter images with daily and hourly-modeled snow surface wetness and temperature showed that the model agreed with the backscatter for snow surface wetness on some days but not on others. Factors such as NSCAT overpass times, vegetation on the ground and their freeze-thaw state, and liquid moisture content appear to contribute to these discrepancies.     

Chemical characterization of native wild plants of dry seasonal forests of the semi-arid region of northeastern Brazil

The present study seeks to increase the knowledge of the chemical and nutritional characteristics of the species in the Caatinga (semi-arid region from northeastern Brazil) and quantify total anthocyanins, flavonols and carotenoids that are in the native food resources. Nine species were selected from ethnobotanical survey conducted in two rural communities in northeastern Brazil. The study revealed the potential of various food plants in the Caatinga, especially in comparison to other wild species of the same genus that have been investigated in other studies. The following species are of interest for future studies on bioactive substances: Eugenia sp. and Sideroxylon obtusifolium. It is interesting to investigate the potential agroindustry of the latter species, along with Syagrus cearensis and Ziziphus joazeiro. Nevertheless, the most immediate impact of this study may be to improve the populations' use of species such as S. cearensis, S. obtusifolium, and Eugenia sp., which have elevated nutritional potential and could be used in programs to improve the quality of food among the rural population.     

Understanding and realizing presence in the Presenccia project.

People who experience an immersive VR system usually report feeling as if they were really in the displayed virtual situation, and can often be observed behaving in accordance with that feeling, even though they know that they're not actually there. Researchers refer to this feeling as "presence" in virtual environments, yet the term has come to have many uses and meanings, all of which evolved from the notion of telepresence in teleoperator systems. In Presenccia, we take an operational approach to the presence concept. Our approach lets us assess the extent of presence using tools beyond traditional questionnaires, and therefore we avoid many of the problems involved with sole reliance on these. Instead, we consider the extent to which mixed reality (MR) and VR participants realistically respond to virtually generated sensory data. Specifically, we measure the similarity of their response with what we might observe or predict if the sensory data-the situation, place, or events-were real, rather than virtual. We consider this response on several levels.     

Social cooperation and competition in the mixed reality space eXperience Induction Machine XIM

Although the architecture of mixed reality spaces is becoming increasingly more complex, our understanding of human behavior in such spaces is still limited. Despite the sophisticated methods deployed in ethology and behavioral biology to track and analyze the actions and movements of animals, we rarely find studies that focus on the understanding of human behavior using such instruments. Here, we address this issue by analyzing social behavior and physical actions of multiple humans who are engaging in a game. As a paradigm of social interaction, we constructed a mixed reality football game in which two teams of two players have to cooperate and compete in order to win. This paradigm was deployed in the, so-called, eXperience Induction Machine (XIM), a human accessible, fully instrumented space that supports full body interaction in mixed reality without the need for body-mounted sensors. Our results show that winning and losing strategies can be discerned by specific behavioral patterns and proxemics. This demonstrates that mixed reality systems such as XIM provide new paradigms for the investigation of human social behavior.