Distributed convex optimization via continuous-time coordination algorithms with discrete-time communication

This paper proposes a novel class of distributed continuous-time coordination algorithms to solve network optimization problems whose cost function is a sum of local cost functions associated to the individual agents. We establish the exponential convergence of the proposed algorithm under (i) strongly connected and weight-balanced digraph topologies when the local costs are strongly convex with globally Lipschitz gradients, and (ii) connected graph topologies when the local costs are strongly convex with locally Lipschitz gradients. When the local cost functions are convex and the global cost function is strictly convex, we establish asymptotic convergence under connected graph topologies. We also characterize the algorithm's correctness under time-varying interaction topologies and study its privacy preservation properties. Motivated by practical considerations, we analyze the algorithm implementation with discrete-time communication. We provide an upper bound on the stepsize that guarantees exponential convergence over connected graphs for implementations with periodic communication. Building on this result, we design a provably-correct centralized event-triggered communication scheme that is free of Zeno behavior. Finally, we develop a distributed, asynchronous event-triggered communication scheme that is also free of Zeno with asymptotic convergence guarantees. Several simulations illustrate our results.Comment: 12 page

Cooperative localization for mobile agents: a recursive decentralized algorithm based on Kalman filter decoupling

We consider cooperative localization technique for mobile agents with communication and computation capabilities. We start by provide and overview of different decentralization strategies in the literature, with special focus on how these algorithms maintain an account of intrinsic correlations between state estimate of team members. Then, we present a novel decentralized cooperative localization algorithm that is a decentralized implementation of a centralized Extended Kalman Filter for cooperative localization. In this algorithm, instead of propagating cross-covariance terms, each agent propagates new intermediate local variables that can be used in an update stage to create the required propagated cross-covariance terms. Whenever there is a relative measurement in the network, the algorithm declares the agent making this measurement as the interim master. By acquiring information from the interim landmark, the agent the relative measurement is taken from, the interim master can calculate and broadcast a set of intermediate variables which each robot can then use to update its estimates to match that of a centralized Extended Kalman Filter for cooperative localization. Once an update is done, no further communication is needed until the next relative measurement

Pajanan Whole Body Vibration dan Risiko Low Back Pain pada Supir

Low back pain (LBP) adalah rasa nyeri di daerah punggung bawah berupa nyeri lokal, radikuler, maupun keduanya. LBP merupakan keluhan yang timbul akibat berbagai faktor, termasuk faktor pekerjaan. Berbagai penelitian menunjukkan bahwa whole body vibration (WBV) adalah salah satu faktor. Paparan WBV selama bekerja dapat meningkatkan risiko LBP. Salah satu pekerjaan dengan paparan WBV adalah supir. Didapatkan dua studi kohort yang terpilih untuk dilakukan critical appraisal. Terdapat dua artikel yang digunakan, yaitu Bovenzi dan Tiemessen et al. Subjek tiap penelitian berjumlah 537 dan 229 orang. Masing-masing menunjukkan RR 1,46 dan 1,05 yang belum cukup kuat untuk dikategorikan sebagai faktor risiko LBP.  Namun, variabel lain, seperti driving related LBP, intensitas nyeri, dan disabilitas disebut memiliki hubungan dengan WBV. Paparan WBV dapat meningkatkan risiko terjadinya LBP pada supir

Pengaruh Budaya Organisasi terhadap Kualitas Sistem Informasi Akuntansi Manajemen Serta Implikasinya terhadap Kinerja Manajerial

Penelitian ini bertujuan untuk mengetahui besar pengaruh budaya organisasiterhadap kualitas sistem informasi akuntansi manajemen serta implikasinya terhadapkinerja manajerial. Perusahaan yang dimaksud sebagai objek penelitian adalah PT.Esa Kirana Nusa Bandung. Penelitian ini dikaji dengan metode penelitian kuantitatifserta teknik pengumpulan data berupa penelitian lapangan kuisioner yang disebarkankepada 38 responden. Alat analisis yang digunakan merupakan metode structuralequation modeling (SEM) berbasis struktur variance yang disebut sebagai least squarepath modeling (PLS-PM) menggunakan bantuan software Smart-PLS. Hasil penelitian menunjukan bahwa budaya organisasi berpengaruh positif dan signifikan terhadapkualitas sistem informasi akuntansi manajemen. Kualitas sistem informasi akuntansimanajemen berpengaruh positif dan signifikan terhadap kinerja manajerial. &nbsp

Una estrategia eficaz para fomentar la cooperación

Some meta-analysis studies that show the efficacy of Cooperative Learning in comparison with competitive or individual learning are analyzed. Efficacy is based on the following data: achievement, high levels of reasoning, time required to accomplish the task, transference of learning, intrinsic motivation, cognitive and social development, personal interactions, friendship, reduction of stereotypes and prejudices, mental health, self-esteem, social competencies, internalization of values and the quality of the learning environment. All the available data suggest that it is a strategy that can respond to the challenges that come with globalization

The Drawings and Watercolours By Rear Admiral Frederick William Beechey, F.R.S., P.R.G.S. (1796-1856) In The Collection of The Arctic Institute of North America, University of Calgary

Presents a biography of Frederick Beechy including a discussion of his contributions to the scientific observation of the Arctic. An illustrated catalogue of Beechy's drawings and watercolours is accompanied by matching descriptive excerpts from rare expedition narratives