Continuous-time Proportional-Integral Distributed Optimization for Networked Systems

In this paper we explore the relationship between dual decomposition and the consensus-based method for distributed optimization. The relationship is developed by examining the similarities between the two approaches and their relationship to gradient-based constrained optimization. By formulating each algorithm in continuous-time, it is seen that both approaches use a gradient method for optimization with one using a proportional control term and the other using an integral control term to drive the system to the constraint set. Therefore, a significant contribution of this paper is to combine these methods to develop a continuous-time proportional-integral distributed optimization method. Furthermore, we establish convergence using Lyapunov stability techniques and utilizing properties from the network structure of the multi-agent system.Comment: 23 Pages, submission to Journal of Control and Decision, under review. Takes comments from previous review process into account. Reasons for a continuous approach are given and minor technical details are remedied. Largest revision is reformatting for the Journal of Control and Decisio

A two-step approach for interest estimation from gaze behavior in digital catalog browsing

While eye gaze data contain promising clues for inferring the interests of viewers of digital catalog content, viewers often dynamically switch their focus of attention. As a result, a direct application of conventional behavior analysis techniques, such as topic models, tends to be affected by items or attributes of little or no interest to the viewer. To overcome this limitation, we need to identify “when” the user compares items and to detect “which attribute types/values” reflect the user’s interest. This paper proposes a novel two-step approach to addressing these needs. Specifically, we introduce a likelihood-based short-term analysis method as the first step of the approach to simultaneously determine comparison phases of browsing and detect the attributes on which the viewer focuses, even when the attributes cannot be directly obtained from gaze points. Using probabilistic latent semantic analysis, we show that this short-term analysis step greatly improves the results of the subsequent step. The effectiveness of the framework is demonstrated in terms of the capability to extract combinations of attributes relevant to the viewer’s interest, which we call aspects, and also to estimate the interest described by these aspects

Manipulability of Leader-Follower Networks with the Rigid-Link Approximation

© Elsevier. This is the author's version of a work that was accepted for publication in Automatica. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Automatica, Vol. 50, Issue 3, pp. 695-706, March 2014, doi: 10.1016/j.automatica.2013.11.041DOI: 10.1016/j.automatica.2013.11.041This paper introduces the notion of manipulability to mobile, multi-agent networks as a tool to analyze the instantaneous effectiveness of injecting control inputs at certain, so-called leader nodes in the network. Effectiveness is interpreted to characterize how the movements of the leader nodes translate into responses among the remaining follower nodes. This notion of effectiveness is a function of the interaction topologies, the agent configurations, and the particular choice of inputs used to influence the network. In fact, classic manipulability is an index used in robotics to analyze the singularity and efficiency of configurations of robot-arm manipulators. To define similar notions for leader-follower networks, we use a rigid-link approximation of the follower dynamics and, under this assumption, we prove that the instantaneous follower velocities can be uniquely determined from that of the leaders’, which allows us to define a meaningful and computable manipulability index for the leader-follower networks. This paper examines the property of the proposed index in simulation and with real mobile robots, and demonstrates how the index can be used to find effective interaction topologies

Approximate Manipulability of Leader-Follower Networks

© 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Presented at the 50th IEEE Conference on Decision and Control and European Control Conference, December 12-15, 2011, Orlando, FL, USA.We introduce the notion of manipulability to leader-follower networks as a tool to analyze how effective inputs injected at a leader node are in terms of their impact on the movements of the follower nodes, as a function of the interaction topologies and agent configurations. Classic manipulability is an index used in robotics for analyzing the singularity and efficiency of configurations of robot-arm manipulators. To define similar notions for leader-follower networks, we use a rigid-link approximation of the follower dynamics and under this assumption, we prove that the instantaneous follower velocities can be uniquely determined by that of the leader's, which allows us to define a meaningful manipulability index of the leader-follower network

Endogenous Inequality

Does the market economy exacerbate inequality across households? In a capitalistick society, does the rich maintain a high level of wealth at the expense of the poor? Or would an accumulation of the wealth by the rich eventually trickle down to the poor and pull the latter out of poverty? This paper presents a theoretical framework, in which one can address these questions in a systematic way. The model focuses on the role of credit market, which determines the joint evolution of the distribution of wealth and the interest rate. A complete characterization of the steady states is provided. Under some configurations of the parameter values, the model predicts an endogenous and permanent separation of the population into the rich and the poor, where the rich maintains a high level of wealth partially due to the presence of the poor. Under others, the model predicts the Kuznets curve, i.e., the wealth eventually trickles down from the rich to the poor, eliminating inequality in the long run.Imperfect Credit Markets, Distribution of Wealth, Endogenous Inequality, Trickle-Down, The Kuznets Curve

A probabilistic approach for eye-tracking based process tracing in catalog browsing

Eye movements are an important cue to understand consumer decision processes. Findings from existing studies suggest that the consumer decision process consists of a few different browsing states such as screening and evaluation. This study proposes a hidden Markov-based gaze model to reveal the characteristics and temporal changes of browsing states in catalog browsing situations. Unlike previous models that employ a heuristic rule-based approach, our model learns the browsing states in a bottom-up manner. Our model employs information about how often a decision maker looks at a selected item (the item finally selected by a decision maker) to identify the browsing states. We evaluated our model using eye tracking data in digital catalog browsing and confirmed our model can split decision process into meaningful browsing states. Finally, we propose an estimation method of browsing states that does not require the information of the selected item for applications such as an interactive decision support

A Boy with Non-Herpes Simplex Acute Limbic Encephalitis and Antiglutamate Receptor Antibodies

This report concerns a 12-year-old male with intractable seizures over a long period. The case fulfilled the diagnostic criteria for nonherpetic acute limbic encephalitis. He had frequent convulsions starting with a partial seizure at the left angle of the mouth and progressing to secondary generalized seizures. He was treated with several anticonvulsants, combined with methylprednisolone and γ-globulin under mechanical ventilation. However, his convulsions reappeared after tapering of the barbiturate. His magnetic resonance imaging showed a high intensity area in the hippocampus by FLAIR and diffusion. After five months he recovered without serious sequelae. Virological studies, including for herpes simplex virus, were all negative. He was transiently positive for antiglutamate receptor antibodies in cerebrospinal fluid and serum

Development and validation of the short version of metacognitions questionnaire-Insomnia

Waine, Broomfield, Banham, & Espie (2009) developed and validated the Metacognitions Questionnaire-Insomnia (MCQ-I) to assess metacognition about sleep, which was hypothesized to have a two-factor structure consisting of metacognitive belief about sleep, and metacognitive plans about sleep. However, it is unclear if the MCQ-I reflects metacognition about sleep as hypothesized because no item analysis or factor analysis was conducted. The present study was designed to develop a short version of MCQ-I using selected items and investigate its reliability and validity. A cross-sectional survey using the MCQ-I was conducted with undergraduates (N=330) and 27 patients with chronic insomnia disorder. Results of factor analysis and item analysis of their responses indicated that MCQ-I has a two-factor structure as hypothesized, and 25 items had high internal consistency. Moreover, the MCQ-I-25 was correlated with metacognition about worry, comprehensive dimensions of cognitive arousal, and sleep disturbances. Furthermore, the MCQ-I-25 score was higher in insomnia patients than healthy students. These results suggest that MCQ-I-25 reflects metacognition about sleep and could predict cognitive arousal and insomnia

Improvement Of Centrifugal Compressor Reliability Handling High Pressure And High Density Gas.

LecturePg. 51-60Centrifugal compressors handling high pressure and high density gas can sometimes encounter trouble such as rotor instability and impeller resonance vibration while in operation. In order to eliminate these problems, various analytical and experimental studies were carried out. Shop verification tests were performed to corroborate the studies and to confirm demonstrated improvement in the reliability of the compressors. Reliability improvements in the above two areas-namely compressor rotor stability and impeller resonanceare described in this paper, with specific reference to newly developed knowledge and technology for the benefit of interested centrifugal compressor users and turbomachinery engineers

How to evaluate science problem solving in a computerized learning environment? Construction of an analyzing scheme

Περιέχει το πλήρες κείμενοThis paper describes the construction of a ‘computerized science problem solving’ scheme, which enables analysis and evaluation of the effectiveness of science problem-solving by junior high-school students working in a computerized learning environment. The scheme was based on observations of 187 students as they solved qualitative science problems taken from a specific computerized learning environment. Students were also interviewed before and after the problem solving. The scheme is presented on two levels. The large-scale comprises 11 main categories, each sub-divided into sub-categories to yield the detailed-level. The sub-categories were based on a repertoire of activities found in the observation protocols, and were approved by external judgement and a validation process. The detailed-level scheme enables evaluation and statistical analysis of the participants' problem-solving effectiveness, providing substantial evidence for the construct validity of the scheme, and demonstrating its potential as a valid analyzing and evaluative tool for computerized science problem solving