Collection Path Research Articles

Organic photovoltaics with thick active layers (∼800 nm) using a high mobility polymer donor

Rather consistent power conversion efficiencies have been achieved in organic solar cells throughout a wide range of active layer thicknesses (∼100nm to ∼800nm) by using a p-type polymer semiconductor with high hole transport mobility (∼1cm2V−1s−1) as the donor, and PC61BM as the acceptor. A comparison between standard and inverted device configurations demonstrates that the inverted configuration is more suitable for achieving thicker active layers when a high hole mobility donor is used. We attribute this to the longer hole collection path in the inverted structure, which can benefit from using a high hole mobility material. Our results will be very useful for the development of new semiconductor materials and the design of device structures for more feasible manufacturing of large area OPV devices via high speed roll-to-roll printing processes.

Ant Colony Optimization for task allocation in Multi-Agent Systems

Task allocation is a key issue of agent cooperation mechanism in Multi-Agent Systems. The important features of an agent system such as the latency of the network infrastructure, dynamic topology, and node heterogeneity impose new challenges on the task allocation in Multi-Agent environments. Based on the traditional parallel computing task allocation method and Ant Colony Optimization (ACO), a novel task allocation method named Collection Path Ant Colony Optimization (CPACO) is proposed to achieve global optimization and reduce processing time. The existing problems of ACO are analyzed; CPACO overcomes such problems by modifying the heuristic function and the update strategy in the Ant-Cycle Model and establishing a three-dimensional path pheromone storage space. The experimental results show that CPACO consumed only 10.3% of the time taken by the Global Search Algorithm and exhibited better performance than the Forward Optimal Heuristic Algorithm.

Evaluation method for Raman depolarization measurements including geometrical effects and polarization aberrations

In this article, we address the notoriously difficult problem to quantitatively link measured Raman depolarization values to theoretical polarizability tensor quantities, since quantum calculations do not incorporate experimental parameters. For this, we introduce a numerical model to calculate, for realistic experimental configurations, effective Raman line strength functions, Φ, which find their way into depolarization ratios, ρ. The model is based on interlinked integrations over the angles in the light collection path and a finite Raman source volume along the excitation laser beam. The model deals also with the conditional aperture parameters, associated with more than one optical component in the light collection path. Finally, we also can take into account polarization aberrations introduced by the sample cell windows. The procedure was fully tested for Raman depolarization spectra of selected hydrogen isotopologues. Distinct aspects affecting Raman depolarization data were validated, namely: (1) excitation polarization impurities; (2) extended Raman excitation volumes; (3) Raman light collection over finite solid angles; and (4) polarization aberrations introduced by optics in the light collection path. The correction of the experimental measurement data for the aforementioned effects resulted in depolarization ratios for the Q1(J " ) Raman lines of H2 and T2, which mostly differed by less than 5% from those obtained by quantum‐calculations. Copyright © 2013 John Wiley & Sons, Ltd.

Using GPS and recall to understand water collection in Kenyan informal settlements

This paper uses interviews and Global Positioning System (GPS) loggers to measure the time taken to collect water in two large informal settlements in Kenyan cities. Collection times were measured, and collection paths mapped, in two low-income urban settlements, comparing water access conditions in Nyalenda in Kisumu (where the utility has introduced a new piped water system) with Kibera in Nairobi (where no such improvement has been made). The use of GPS tracking provides a better understanding of time spent collecting water compared to interview data, but the two methods combined provide insights that neither could have suggested alone.

Operation costs and pollutant emissions reduction by definition of new collection scheduling and optimization of MSW collection routes using GIS. The case study of Barreiro, Portugal

This work proposes an innovative methodology for the reduction of the operation costs and pollutant emissions involved in the waste collection and transportation. Its innovative feature lies in combining vehicle route optimization with that of waste collection scheduling. The latter uses historical data of the filling rate of each container individually to establish the daily circuits of collection points to be visited, which is more realistic than the usual assumption of a single average fill-up rate common to all the system containers. Moreover, this allows for the ahead planning of the collection scheduling, which permits a better system management. The optimization process of the routes to be travelled makes recourse to Geographical Information Systems (GISs) and uses interchangeably two optimization criteria: total spent time and travelled distance. Furthermore, rather than using average values, the relevant parameters influencing fuel consumption and pollutant emissions, such as vehicle speed in different roads and loading weight, are taken into consideration. The established methodology is applied to the glass-waste collection and transportation system of Amarsul S.A., in Barreiro. Moreover, to isolate the influence of the dynamic load on fuel consumption and pollutant emissions a sensitivity analysis of the vehicle loading process is performed. For that, two hypothetical scenarios are tested: one with the collected volume increasing exponentially along the collection path; the other assuming that the collected volume decreases exponentially along the same path. The results evidence unquestionable beneficial impacts of the optimization on both the operation costs (labor and vehicles maintenance and fuel consumption) and pollutant emissions, regardless the optimization criterion used. Nonetheless, such impact is particularly relevant when optimizing for time yielding substantial improvements to the existing system: potential reductions of 62% for the total spent time, 43% for the fuel consumption and 40% for the emitted pollutants. This results in total cost savings of 57%, labor being the greatest contributor, representing over €11,000 per year for the two vehicles collecting glass-waste. Moreover, it is shown herein that the dynamic loading process of the collection vehicle impacts on both the fuel consumption and on pollutant emissions.

Heterojunction Silicon Microwire Solar Cells

We report radial heterojunction solar cells of amorphous silicon on crystalline silicon microwires with high surface passivation. While the shortened collection path is exploited to increase the photocurrent, proper choice of the wire radius and the highly passivated surface prevent drastic decrease in the voltage due to high surface-to-volume ratio. The heterojunction is formed by depositing a ∼12-16 nm of amorphous silicon on crystalline silicon wires of radius approximately equal to minority carrier diffusion length (∼10 μm). In spite of very short carrier lifetime (<1 μs), the microwire array devices generate photocurrent of ∼30 mA/cm(2), and the same time, voltages close to 600 mV are achieved, leading to efficiency in excess of 12% in extremely short carrier lifetime silicon. We also find that formation of nanocrystallites of silicon in the deposited film results in loss of the expected passivation.

Multicore fiber with integrated fiber Bragg gratings for background-free Raman sensing

In the last years a variety of fiber optic Raman probes emerged, which are only partly suited for in vivo applications. The in vivo capability is often limited by the bulkiness of the probes. The size is associated with the required filtering of the probes, which is necessary due to Raman scattering inside the fibers. We employed in-line fiber Bragg gratings (FBG) as notch filter for the collection path and integrated them in a novel type of Raman probe. Multicore singlemode fibers (MCSMF) were designed and drawn integrating 19 singlemode cores to achieve better collection efficiency. A Raman probe was assembled with one excitation fiber and six MCSMF with inscribed FBGs as collection fibers. The probe was characterized regarding Raman background suppression, collection efficiency, and distance dependence. First Raman measurements on brain tissue are presented.

A survey of peer-to-peer live video streaming schemes – An algorithmic perspective

Live video streaming applications have gained great popularity among users but exert great pressure on video servers and the Internet. Peer-to-Peer (P2P) networks provide an attractive solution due to their low cost and high scalability. A large number of P2P live video streaming schemes have been proposed and many deployments have appeared on the Internet. These schemes pursue vastly diverse directions, from mimicking IP multicast to BitTorrent-like swarming to distributed hash tables. In this paper, we provide a comprehensive and in-depth survey of P2P live video streaming schemes from an algorithmic perspective. Our purpose is to acquaint future designers with the critical design choices and their impacts on system performance. The primary objective of a P2P live video streaming system is to distribute packets from the video source to peers, and the collective paths through which a packet traverses form a tree. We focus on three aspects of how these trees are formed: determining the supplier–receiver relationships for each packet, handling the departure of the supplier or receiver before their relationship expires, and handling lost packets. We identify critical design choices in each aspect and propose a taxonomy according to these choices. Because the surveyed papers use different performance metrics and the reported results are heavily influenced by their experimental settings, we consider two measures to identify the impact of each design choice: we use a set of “internal” metrics in addition to the commonly used “external” metrics, and we examine performance metrics of schemes that have made the same design choice. For better understanding of how the design choices interact with one another and exposing future designers to the design choices specific to each individual scheme, we also provide systematic summaries for a large number of schemes.

DQSB: A Reliable Broadcast Protocol Based on Distributed Quasi-Synchronized Mechanism for Low Duty-Cycled Wireless Sensor Networks

In duty-cycled wireless sensor networks, deployed sensor nodes are usually put to sleep for energy efficiency according to sleep scheduling approaches. Any sleep scheduling scheme with its supporting protocols ensures that data can always be routed from source to sink. In this paper, we investigate a problem of multi-hop broadcast and routing in random sleep scheduling scheme, and propose a novel protocol, called DQSB, by quasi-synchronization mechanism to achieve reliable broadcast and less latency routing. DQSB neither assumes time synchronization which requires all neighboring nodes wake up at the same time, nor assumes duty-cycled awareness which makes it difficult to use in asynchronous WSNs. Furthermore, the benefit of quasi-synchronized mechanism for broadcast from sink to other nodes is the less latency routing paths for reverse data collection to sink because of no or less sleep waiting time. Simulation results show that DQSB outperforms the existing protocols in broadcast times performance and keeps relative tolerant broadcast latency performance, even in the case of unreliable links. The proposed DQSB protocol, in this paper, can be recognized as a tradeoff between broadcast times and broadcast latency. We also explore the impact of parameters in the assumption and the approach to get proper values for supporting DQSB.

Confronting Sexual Assault: Transformative Justice on the Ground in Philadelphia

Confronting Sexual Assault: Transformative Justice on the Ground in Philadelphia

Route Optimisation for Solid Waste Management Using GeoInformatics

Due to rapid industrialisation, population of Chandrapur city of Maharashtra state of India is increasing day by day, hence increasing the solid waste generation. Around 0.25 kg /person/day solid waste is generated and around 80 ton wastes are dumped in dumping site daily. Collection and transportation is one of the important functional components of solid waste management. Thus, to keep city clean and environmentally healthy, the management of solid waste has now becoming an important issue. Geo-informatics is proposed to determine the minimum cost/distance efficient collection paths for transporting the solid wastes to the dumping site. This uses information on population density, waste generation capacity, road network, storage bins and collection vehicles etc. This paper attempted to optimise the route for collection and transportation of municipal solid waste of the city using geo-informatics technique. Initially all ancillary data have been collected from various sources. Using hand held GPS, the position of the entire dust bin in the city are collected and the data are converted into shape file. The roads are digitised from the road network map of the municipal corporation. From the shape file of existing road network, network database for the entire road are prepared using Arc-GIS 9.2. Taking capacity of solid waste carrying vehicle into consideration, the routes are optimised for each trip of vehicle and total distance to be travelled is calculated for each trip. Finally cost is compared for solid waste disposal using this technique with the existing system of Municipal Corporation. From the analysis and results, it is concluded that the Geo-informatics technique gives better accuracy for route optimisation and can be used as a decision support tool by municipal authorities for efficient management of the daily operations for transporting solid wastes, load balancing within vehicles, managing fuel consumption and generating work schedules for the workers and vehicles for overall cost minimisation.

Living With HIV/AIDS: A Psychosocial Perspective on Coping With Prejudice and Discrimination1

We examined 2 strategies used by people with HIV (N = 68) to cope with the effects of prejudice and discrimination: hiding of stigma and in-group identification. In support of the first proposed path, we found that group-based discrimination enhanced hiding of stigma. This reduces the perception of personal discrimination; and this, in turn, is positively related to well-being. We also found evidence for a second, more collective path by which those who are HIV-positive protect their well-being. Perceived group-based discrimination was positively associated with in-group identification, which, in turn, was positively related to collective action intentions and well-being. The discussion focuses on how well-being can be protected through both individual- and group-level processes.

Step-Coupler for Efficient Waveguide Coupling to Ge/Si Avalanche Photodetectors

In recent years, Ge/Si avalanche photodiodes (APDs) have shown significant potential in high-sensitivity and high-speed photodetection for optical communications. Waveguide-coupling can further increase the bandwidth-efficiency product of these devices by separating the optical absorption path from the carrier collection path. Here we present a step-coupler design for efficient vertical coupling between Si waveguides and Ge/Si APDs. The step-coupler approach can achieve >;70% absorption with a 10-μm-long Ge absorption region at λ = 1550 nm, 5 X reduction in device length compared to the conventional waveguide coupling. The significant increase in coupling efficiency is due to vertical multimode interference (MMI) that enhances light scattering towards the Ge active region and creates mirror images of optical modes close to the Ge layer.

Optimizing data collection path in sensor networks with mobile elements

Exploiting mobile elements (MEs) to accomplish data collection in wireless sensor networks (WSNs) can improve the energy efficiency of sensor nodes, and prolong network lifetime. However, it will lead to large data collection latency for the network, which is unacceptable for data-critical applications. In this paper, we address this problem by minimizing the traveling length of MEs. Our methods mainly consist of two steps: we first construct a virtual grid network and select the minimal stop point set (SPS) from it; then, we make optimal scheduling for the MEs based on the SPS in order to minimize their traveling length. Different implementations of genetic algorithm (GA) are used to solve the problem. Our methods are evaluated by extensive simulations. The results show that these methods can greatly reduce the traveling length of MEs, and decrease the data collection latency.

Singing in Animal Tongues: An Inner Journey

nimal tongues” is a language I speak and sing. It acts as a bridge to the world beneath the surface, and it enables me to live and see clearly. It is the voice of the Other—the animal soul, consciousness, and spirit. Animal tongues is not a literal portrayal of animal sounds, but it expresses the animal spirit within human beings and within the world through speaking and singing in tongues. High and low voices, innocent and knowledgeable, interact in a ritual of chanting and singing. The origins of my speaking in animal tongues can be traced to my earliest memories. All of the events in my life, all of the different forms my art would take, have contributed to and led to this language, which is part of my identity. The animals are within us, within our subconscious. I see a connection with phylogeny, as the beings in animal tongues are re-living all of our collective paths. They remind us of our connections with other animals, with the earth, with ourselves, and with nature. I have recollections from my childhood of imaginary friends, private worlds, and communication with both domestic and feral animals in the neighborhood where I lived in south Florida in the 1950s. My father left when I was seven, and I was raised by my mother. It was a solitary life, as we were forced to move often because we couldn’t afford to pay the rent. Although briefly exposed to traditional religion in my childhood, I was reluctant to connect with it. For instance, when my mother sent me to walk to church on Sundays, I would take a detour, and would go instead to a wild-looking garden, where I could feel empathy with the spiders, lizards, birds, cats, and dogs. This may be the source of my connections with deep ecology and ecotheology, but of course I didn’t call it that back then. Feeling great empathy with the natural world, I would disconnect from the dysfunctional events around me enter abandoned houses, and create worlds that often included animals. Narratives would come into being as a result of what I saw and experienced while spending time alone in the houses or the gardens. The narratives I told as a child would often involve animals and humans communicating with each other, expressing what they loved and feared in the world. One

Beyond mean-field approach to heavy-ion reactions around the Coulomb barrier

Dissipation and fluctuations of one-body observables in heavy-ion reactions around the Coulomb barrier are investigated with a microscopic stochastic mean-field approach. By projecting the stochastic mean-field dynamics on a suitable collective path, transport coefficients associated with the relative distance between colliding nuclei and a fragment mass are extracted. Although microscopic mean-field approach is know to underestimate the variance of fragment mass distribution, the description of the variance is much improved by the stochastic mean-field method. While fluctuations are consistent with the empirical (semiclassical) analysis of the experimental data, concerning mean values of macroscopic variables the semiclassical description breaks down below the Coulomb barrier.

Graphene Electronics: High‐Gain Graphene‐Titanium Oxide Photoconductor Made from Inkjet Printable Ionic Solution (Adv. Mater. 46/2010)

A solution-processible approach to fabricating hybrid TiO2-graphene photoconducting matrices that are printable and spin-castable is reported on p. 5265 by Kian Ping Loh and co-workers. The technique produces extended heterojunctions of TiO2 and graphene, permitting short collection paths for electrons. Such a solution-based approach affords chemical tunability and easy film formation, and holds considerable innovation potential for carbon-based printable optoelectronic devices.

Corrected High–Frame Rate Anchored Ultrasound With Software Alignment

To improve lingual ultrasound imaging with the corrected high frame rate anchored ultrasound with software alignment (CHAUSA; Miller, 2008) method. A production study of the IsiXhosa alveolar click is presented. Articulatory-to-acoustic alignment is demonstrated using a Tri-Modal 3-ms pulse generator. Images from 2 simultaneous data collection paths, using dominant ultrasound technology and the CHAUSA method, are compared. The probe stabilization and head movement correction paradigm is demonstrated. The CHAUSA method increases the frame rate from the standard National Television System Committee (NTSC) video rate (29.97) to the ultrasound internal machine rate--in this case, 124 frames per second (fps)--by using Digital Imaging and Communications in Medicine (DICOM; National Electrical Manufacturers Association, 2008) data transfer. DICOM avoids spatiotemporal inaccuracies introduced by dominant ultrasound export techniques. The data display alignment of the acoustic and articulatory signals to the correct high-frame rate (FR) frame (± 4 ms at 124 fps). CHAUSA produces high-FR, high-spatial-quality ultrasound images, which are head corrected to 1 mm. The method reveals tongue dorsum retraction during the posterior release of the alveolar click and tongue tip recoil following the anterior release of the alveolar click, both of which were previously undetectable. CHAUSA visualizes most of the tongue in studies of dynamic consonants with a major reduction in field problems, opening up important areas of speech research.

Near-infrared Raman spectroscopy using hollow-core photonic bandgap fibers

We report a NIR Raman spectroscopy system incorporating hollow-core photonic bandgap fibers (HC-PBFs) in both the excitation and collection paths. Raman excitation was achieved at NIR laser wavelength of 785nm. We demonstrate that using HC-PBFs, Raman spectroscopy can be performed without the use of an additional longpass filter on the collection side. A narrow bandpass filter on the excitation side is also not required. These results provide a framework where HC-PBF based Raman probes can be developed and used in space restricted biomedical and sensing applications.

Calibration methods for ITER core LIDAR

The standard technique for the relative calibration in present Thomson scattering diagnostics, can be used in ITER only if the full collection path is included in the calibration: indeed, the in-vessel optics will be exposed to neutron and gamma irradiation and particle flux, that will likely cause a distortion of the spectral transmission curve. The standard scheme would ask to position a diffuser in front of the first collection mirror, e.g. on the protective shutter, and to illuminate it with a light source nearby. Alternatively, a back illumination scheme could be used, with a more efficient retroreflector array. A completely different approach is based on TS measurements from two lasers with different wavelengths: this self-calibrating method does not require any in-vessel tool and will provide both the electron temperature and the relative sensitivity of spectral channels.