Selective Idling: Experiments in Transport Layer Energy Conservation

In this paper we consider the potential of using an aggressive form of energy conservation for mobile computing environments. The estimators for the round-trip time and round-trip time variance used by TCP are used to direct the transceiver of a mobile node to idle over extended periods of time when packet activity is not anticipated. In addition, we consider data link layer extensions that provide additional control information allowing the mobile to be further selective as to when to idle and when to activate the network interface device. Simulations are conducted to examine the performance of the proposed scheme under various levels of congestion in the fixed part of the network, from completely unloaded to fully congested. The simulations reveal that the technique is promising but its effectiveness depends crucially on the control of the maximum window size used by TCP and on accurate knowledge of the congestion conditions in the network.     

Aggregation convergecast scheduling in wireless sensor networks

We consider the problem of scheduling in wireless sensor networks for the purposes of aggregation convergecast. We observe that existing schemes adopt essentially a two phase approach, consisting of, first, a tree construction and, second, a scheduling phase. Following a similar approach, we propose two new improvements, one to each of the two phases. Starting with a new lower bound on the schedule length, we make use of it in the tree construction phase. The tree construction phase consists of solutions to instances of bipartite graph semi-matchings. The scheduling phase is a weight-based priority scheme that obeys dependency (tree) and interference constraints. Our extensive experiments show that, overall, our proposed solution not only outperforms all previously proposed solutions in terms of schedule length, but it also significantly extends the network’s lifetime.     

Preliminary investigations of an amperometric oligosaccharide dehydrogenase-based electrode for the detection of glucose and some other low molecular weight saccharides

Biosensors for the determination of sugars were constructed using oligosaccharide dehydrogenase (ODH) and soluble phenazine methosulfate (PMS) or an osmium-based three-dimensional redox hydrogel. In the latter case the enzyme and poly(1-vinylimidazole) complexed with osmium (4,4'-dimethylbpy)2Cl were cross-linked with poly(ethylene glycol) diglycidyl ether. Both electrode configurations showed similar sensitivities for glucose in the range between 8 and 21 muAmM-1 cm-2. The responses for 10 mono and oligosaccharides were studied. There was no response for fructose. In the concentration range 0.1-20 mM the relative sensitivities were determined for arabinose (96%), xylose (3%), mannose (50%), galactose (11%), glucose (100%), maltose (24%), lactose (12%), cellobiose (34%) and maltotriose (10%).     

Stages of psychotherapy: Progressive reconceptualizations as a self-organizing process.

Presents psychotherapy as a process of progressive cognitive reframing leading the individual to higher levels of self-organization. The crucial successive reconceptualizations that are achieved during the process refer to the way the person in therapy perceives oneself in relation to others and to life in general and constitute distinctive steps that are referred to as stages. Successive shifts in the client's frame of mind achieved during the process are inherently connected to a series of crucial decisions that enable therapy to remain goal directed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

L-alpha-glycerophosphate and L-lactate electrodes based on the electrochemical "wiring" of oxidases.

The title electrodes were constructed by coimmobilizing the respective FAD oxidases on solid electrode surfaces with a poly(vinyl pyridine) polymer which was N-derivatized with bromoethylamine and Os(bpy)2Cl2. The redox-polymer-enzyme hydrogels were cross-linked on the electrode surface using poly(ethylene glycol) diglycidyl ether. As in the case of glucose oxidase, the redox polymer acts as an electron relaying "wire" transferring electrons directly from the enzymes' FADH2 centers to the electrode. This transfer competes with the natural process of reoxidation of FADH2 by molecular oxygen. The variation of the response of these electrodes with the atmosphere (N2 or air), pH, and substrate concentration was determined. The pH profile of the electrocatalytic current differs from that of the activity of the free enzymes, exhibiting a broader maximum, shifted to higher pH values. The observed sensitivities and linear ranges are respectively 2 x 10(-2) A M-1 cm-2 and 2.7 mM for L-alpha-glycerophosphate, and 0.3 A M-1 cm-2 and 0.2 mM for L-lactate that may be compared to 2 x 10(-2) A M-1 cm-2 and 10 mM for glucose. The 0-90% response time for all electrodes is 1 s or less.     

An adaptive personalized news dissemination system

With the explosive growth of the Word Wide Web, information overload became a crucial concern. In a data-rich information-poor environment like the Web, the discrimination of useful or desirable information out of tons of mostly worthless data became a tedious task. The role of Machine Learning in tackling this problem is thoroughly discussed in the literature, but few systems are available for public use. In this work, we bridge theory to practice, by implementing a web-based news reader enhanced with a specifically designed machine learning framework for dynamic content personalization. This way, we get the chance to examine applicability and implementation issues and discuss the effectiveness of machine learning methods for the classification of real-world text streams. The main features of our system named PersoNews are: (a) the aggregation of many different news sources that offer an RSS version of their content, (b) incremental filtering, offering dynamic personalization of the content not only per user but also per each feed a user is subscribed to, and (c) the ability for every user to watch a more abstracted topic of interest by filtering through a taxonomy of topics. PersoNews is freely available for public use on the WWW ().

Developing wireless sensor network applications in a virtual environment

We describe our “holistic” platform for developing wireless ad hoc sensor networks and focus on its most representative and essential virtualization component: VUE² (the Virtual Underlay Emulation Engine). Its role is to provide a vehicle for the authoritative emulation of complete networked applications before physically deploying any wireless nodes. The goal is to be able to verify those applications exhaustively before programming the hardware, such that no further (field) tests are necessary. We explain how VUE² achieves this goal owing to several facilitating factors, most notably the powerful programming paradigm that our platform adopts. As implied by the holistic nature of the discussed system, our work touches upon operating systems, simulation, network protocols, real-time systems, and programming methodology.     

Reflections on the state of Greek psychology.

Responds to the articles by J. C. Bouhoutsos and K. V. Roe (see record 1984-26827-001) and by P. Vanger (see record 1987-00005-001) describing clinical and academic psychology in Greece as underdeveloped. The present author explains why developments have been delayed, and recent developments are not discernible to both outsiders and those who are part of the processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning patterns for discovering domain-oriented opinion words

Sentiment analysis is a challenging task that attracted increasing interest during the last years. The availability of online data along with the business interest to keep up with consumer feedback generates a constant demand for online analysis of user-generated content. A key role to this task plays the utilization of domain-specific lexicons of opinion words that enables algorithms to classify short snippets of text into sentiment classes (positive, negative). This process is known as dictionary-based sentiment analysis. The related work tends to solve this lexicon identification problem by either exploiting a corpus and a thesaurus or by manually defining a set of patterns that will extract opinion words. In this work, we propose an unsupervised approach for discovering patterns that will extract domain-specific dictionary. Our approach (DidaxTo) utilizes opinion modifiers, sentiment consistency theories, polarity assignment graphs and pattern similarity metrics. The outcome is compared against lexicons extracted by the state-of-the-art approaches on a sentiment analysis task. Experiments on user reviews coming from a diverse set of products demonstrate the utility of the proposed method. An implementation of the proposed approach in an easy to use application for extracting opinion words from any domain and evaluate their quality is also presented.     

Screen-printed integrated microsystem for the electrochemical detection of pathogens

Fast, reliable, selective and high sensitive pathogen detection from different samples is a necessary requirement in current legislation; besides today's society demands a decrease in the time to detect the presence of pathogens. A low-cost, easy-to-fabricate microsystem, where the electrodes are both structural and functional elements, capable of electrochemically detecting those microorganisms has been manufactured by screen-printing techniques. Capturing of the microorganisms in solution is carried out by paramagnetic immunoparticles that are then electrophoretically immobilized inside the microsystem. Immobilization, lysis and detection of the microorganism are operations that have been integrated inside the microsystem and are constantly electrochemically monitored. The electrochemical detection has been investigated by electrical and electrochemical impedance and by amperometric methods. The electrochemical detection platform shows here concentrations of 10² and 10⁸ CFU/mL have been detected in less than 30-min time since the sample is introduced. The microsystem has a tunable volume down to 10 μL and the whole microsystem has dimensions that open a great window for future applications and implementation in portable pathogen control devices.