Low Power, Low Delay: Opportunistic Routing meets Duty Cycling

Traditionally, routing in wireless sensor networks consists of two steps: First, the routing protocol selects a next hop, and, second, the MAC protocol waits for the intended destination to wake up and receive the data. This design makes it difficult to adapt to link dynamics and introduces delays while waiting for the next hop to wake up. In this paper we introduce ORW, a practical opportunistic routing scheme for wireless sensor networks. In a dutycycled setting, packets are addressed to sets of potential receivers and forwarded by the neighbor that wakes up first and successfully receives the packet. This reduces delay and energy consumption by utilizing all neighbors as potential forwarders. Furthermore, this increases resilience to wireless link dynamics by exploiting spatial diversity. Our results show that ORW reduces radio duty-cycles on average by 50% (up to 90% on individual nodes) and delays by 30% to 90% when compared to the state of the art

Improving performance through concept formation and conceptual clustering

Research from June 1989 through October 1992 focussed on concept formation, clustering, and supervised learning for purposes of improving the efficiency of problem-solving, planning, and diagnosis. These projects resulted in two dissertations on clustering, explanation-based learning, and means-ends planning, and publications in conferences and workshops, several book chapters, and journals; a complete Bibliography of NASA Ames supported publications is included. The following topics are studied: clustering of explanations and problem-solving experiences; clustering and means-end planning; and diagnosis of space shuttle and space station operating modes

On the Error Resilience of Ordered Binary Decision Diagrams

Ordered Binary Decision Diagrams (OBDDs) are a data structure that is used in an increasing number of fields of Computer Science (e.g., logic synthesis, program verification, data mining, bioinformatics, and data protection) for representing and manipulating discrete structures and Boolean functions. The purpose of this paper is to study the error resilience of OBDDs and to design a resilient version of this data structure, i.e., a self-repairing OBDD. In particular, we describe some strategies that make reduced ordered OBDDs resilient to errors in the indexes, that are associated to the input variables, or in the pointers (i.e., OBDD edges) of the nodes. These strategies exploit the inherent redundancy of the data structure, as well as the redundancy introduced by its efficient implementations. The solutions we propose allow the exact restoring of the original OBDD and are suitable to be applied to classical software packages for the manipulation of OBDDs currently in use. Another result of the paper is the definition of a new canonical OBDD model, called {\em Index-resilient Reduced OBDD}, which guarantees that a node with a faulty index has a reconstruction cost $O(k)$, where $k$ is the number of nodes with corrupted index

In vivo and in vitro analysis of RNases in Bacillus subtilis

RNA degradation is a key process in the control of gene expression in bacteria and is essential for the cell’s homeostasis of nucleotide pools. A key player is the so-called RNA degradosome, proposed to be a membrane-associated complex containing endo- and exoribunucleases, as well as glycolytic enzymes and a DEAD-box RNA helicase. It is believed that endonuclease RNase Y is central to the formation of the RNA degradosome in Bacillus subtilis, leading to recruitment of RNases PnpA, RNase J1, and RNase J2, RNA helicase CshA, as well as glycolytic enzymes enolase and phosphofructokinase occurs. RNase Y has a transmembrane helix, and is "quasi“ essential; it is also required for mRNA processing following transcription. RNase Y also interacts with the so-called Y‑complex, consisting of YaaT, YlbF, and, YmcA (RicT, RicF, RicA), which is important for RNase Y-mediated processing of mRNA. How RNase Y can operate in two different protein complexes and acts in RNA decay as well as transcription-associated processes, is unclear. In this work, I show that the RNA degradosome is quite dynamic, having RNase Y, the glycolytic enzyme enolase, and the RNA helicase CshA and PnpA as central parts strongly reacting to a block in transcription, and thus to loss of mRNA substrate, while RNase J1 and J2 as well as the glycolytic enzyme phosphofructokinase show a much weaker response and are thus likely more peripheral components. The Y-complex clearly shows diffusion within the cytosol, but also the formation of membrane-associated accumulations, dissociating when transcription is blocked. Single molecule tracking (SMT) shows that the loss of one component of the Y-complex does not strongly affect the dynamics of the other proteins, suggesting that the complex forms a flexible association rather than a 1:1:1 stoichiometry. Biochemical analyses suggest that YaaT forms a membrane-anchor for the Y-complex, although it also has a cytosolic, freely diffusing fraction. A model will be presented that the Y-complex could function as an adaptor between nucleoid-associated mRNA synthesis and membrane-associated processing and degradation. II My thesis also presents a protocol for the successful purification of membrane-associated RNase Y, as a basis for further biochemical characterization of the protein, and interaction studies. Another essential process in which RNases play a crucial role is DNA replication. In addition to the RNA primers, which are necessary for the placement of Okazaki fragments, DNA/RNA hybrids must be processed and RNA must be removed to ensure the stability of the DNA. A part of the thesis work shows that B. subtilis replication forks intimately employ two RNases of the „H“ family, DNA polymerase A and exonuclease ExoR in vivo. Recruitment appears to be based on substrate availability rather than on specific protein/protein interactions, involving redundant enzymatic activities

The Psychophysiology of Real-Time Financial Risk Processing

A longstanding controversy in economics and finance is whether financial markets are governed by rational forces or by emotional responses. We study the importance of emotion in the decisionmaking process of professional securities traders by measuring their physiological characteristics, e.g., skin conductance, blood volume pulse, etc., during live trading sessions while simultaneously capturing real-time prices from which market events can be defined. In a sample of 10 traders, we find significant correlation between electrodermal responses and transient market events, and between changes in cardiovascular variables and market volatility. We also observe differences in these correlations among the 10 traders which may be systematically related to the traders' levels of experience.

Fitness in contemporary dance: a systematic review.

It has been suggested that dancers are less fit compared to other athletes. However, the majority of studies make their arguments based on data deriving mainly from ballet. Therefore, the aim of the current review was to investigate: a) aerobic and anaerobic fitness, muscular strength and body composition characteristics in contemporary dancers of different levels, and b) whether supplementary exercise interventions, in addition to normal dance training, further improves contemporary dance performance. Three databases (Medline, Cochrane and the Cumulative Index to Nursing & Allied Health research database) were searched to identify publications regarding the main fitness components of contemporary professional and student dancers. At a professional level, it appears that contemporary dancers demonstrate higher maximal oxygen uptake and higher scores in muscular endurance than ballet dancers. However, contemporary dance students are equally fit compared to their ballet counterparts and their body composition is also very similar. Only two studies have investigated the effects of supplementary exercise training on aspects of dance performance. Further research is needed in order to confirm preliminary data, which suggest that the implementation of additional fitness training is beneficial for contemporary dance students to achieve a better performance outcome