Nonlinear filtering problems with finite-dimensional matrix estimation algebras

Matrix estimation algebras are Lie algebras that arise naturally in the nonlinear filtering problem for systems with random structure. These are systems that have finitely many modes of operation, where transitions from one mode to another are governed by a finite-state Markov process. Necessary conditions for finite dimensionality of matrix estimation algebras are given. Finite-dimensional filter realizations are constructed for some of the cases for which the matrix estimation algebra is finite dimensional.     

Order optimal information spreading using algebraic gossip

In this paper we study gossip based information spreading with bounded message sizes. We use algebraic gossip to disseminate $k$ distinct messages to all $n$ nodes in a network. For arbitrary networks we provide a new upper bound for uniform algebraic gossip of $O((k+\log n + D)\varDelta )$ rounds with high probability, where $D$ and $\varDelta $ are the diameter and the maximum degree in the network, respectively. For many topologies and selections of $k$ this bound improves previous results, in particular, for graphs with a constant maximum degree it implies that uniform gossip is order optimal and the stopping time is $\varTheta (k + D)$ . To eliminate the factor of $\varDelta $ from the upper bound we propose a non-uniform gossip protocol, TAG, which is based on algebraic gossip and an arbitrary spanning tree protocol $\mathcal{S } $ . The stopping time of TAG is $O(k+\log n +d(\mathcal{S })+t(\mathcal{S }))$ , where $t(\mathcal{S })$ is the stopping time of the spanning tree protocol, and $d(\mathcal{S })$ is the diameter of the spanning tree. We provide two general cases in which this bound leads to an order optimal protocol. The first is for $k=\varOmega (n)$ , where, using a simple gossip broadcast protocol that creates a spanning tree in at most linear time, we show that TAG finishes after $\varTheta (n)$ rounds for any graph. The second uses a sophisticated, recent gossip protocol to build a fast spanning tree on graphs with large weak conductance. In turn, this leads to the optimally of TAG on these graphs for $k=\varOmega (\text{ polylog }(n))$ . The technique used in our proofs relies on queuing theory, which is an interesting approach that can be useful in future gossip analysis.     

Threat and the majority identity.

This study grapples with the question of majority–minority relations in conflict-ridden societies. The ethnographic study analyzed data gathered in a dialogue course conducted at an Israeli university among Jewish and Palestinian students, all citizens of the State of Israel. The authors identified 4 different and interrelated components of threat as these were perceived by the Jews participating in the dialogue: a permanent existential threat, the realistic threat from Palestinians, the threat to Jewish hegemony in the State of Israel, and the threat to the moral worth of the Jews’ national identity. The authors describe each of these components, how they interrelate, and also the changes undergone by the Jewish participants in the dialogue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chaim Weizmann as a Scientist – From Berlin to the End of His Manchester Period

After finishing high school in Pinsk, Russia, Chaim Weizmann studied two semesters in the Technical University of Darmstadt, returned home for a year, and in 1895 registered as a chemistry student at the Charlottenburg Technical University at Berlin. He studied and worked in the research group of A. Bistrzycki on synthetic dyestuffs and received a patent in the field. He graduated after 3 years and followed Bistrzycki to Freiburg, Switzerland, where he received in January 1899 a Ph.D. degree with a grade of Magna cum laude. He became a Privatdocent at the University of Geneva, worked in Prof. C. Graebe’s group, published papers and patents and sold patents. In 1904, he moved to the University of Manchester in the UK and collaborated with Prof. William Henry Perkin Jr. in research on synthetic dyestuffs and natural products, and started to work with him on the synthesis of acetone by fermentation. He failed to be nominated to Perkin’s chair when Perkin left in 1913, but became a Reader and head of the biochemistry laboratory. After a conflict with Perkin, he continued alone with the acetone synthesis project, found a bacterium that fermented the starch of corn, potatoes, and chestnuts to acetone and butyl alcohol, which was more efficient than a bacterium found by Perkin and co-workers. The urgent need for acetone in World War One for military purpose and the high yield of his bacterium in acetone-producing fermentation, compared with the bacterium of his competitors, made Weizmann’s process the favored one by the British military during the war. Weizmann scaled up acetone production and increased its yield by increasing the sophistication of the process by using a high degree of sterilization. For his contributions he is regarded as the father of industrial biotechnology. His contribution to the war effort opened the door to the British leadership in his Zionistic activity. However, this activity and his scientific activity at later periods are not covered in this article.     

Zeolite membranes for hydrogen production from natural gas: state of the art

Journal of Porous Materials - Currently, hydrogen is produced industrially by processes requiring high energy consumption, especially by cracking fossil fuels and by splitting water. In recent...     

Location and allocation of service units on a congested network

We consider the problem of locating facilities and allocating servers on a congested network (LASCN). Demands for service that originate from the nodes are assumed to be Poisson distributed and the servers provide a service time that is exponentially distributed. The objective is to minimize the total cost of the system which includes a fixed installation cost, a variable server cost, a cost associated with travel time and a cost associated with the waiting time in the facility for all the customers. The problem is formulated using non-linear programming and subsequently analyzed. Results for exact and approximate solution approaches are reported. We also show that we can modify the approaches to solve the LASCN with constraints limiting both the travel time to the servers and the waiting time of customers.     

The design of a collaborative interface for narration to support reconciliation in a conflict

This paper is about the development of a face-to-face collaborative technology to support shifting attitudes of participants in conflict via a narration task. The work is based on two cultural elements: conflict resolution theory and the design of a collaboration enforcing interface designed specifically for the task. The general claim is that participants may achieve a greater understanding of and appreciation for the other’s viewpoint under conditions that support partaking in a tangible joint task and creating a shared narration. Specifically, a co-located interface for producing a joint narration as a tool for favoring reconciliation is presented and discussed. The process based on this technology implicitly includes classical steps in conflict resolution approaches, such as escalation and de-escalation. Our goal is to show that this interface is effective and constitutes an alternative to a typical face-to-face moderated discussion.     

A time-space tradeoff for language recognition

We define a languageL and show that its time and space complexitiesT andS must satisfyT ² S cn ³ even allowing machines with multiple (non random) access to the input.The second author was supported in part by the Israel Commission for Basic Research.     

High-throughput automation design considerations for biotechnology processes involving RNA purification protocols using multi-centrifuge bioseparation steps

Design of an automation line is a multi-objective optimization problem involving throughput, yield, floor space and cost constraints. The paper examines the feasibility of a computer-aided automation design for biotechnology applications using Arena? software. A generic case study chosen for this study involves a sequence of steps in a preparation process of RNA from tissue-cultured cells. These steps involve repetitive usage of centrifuging operations to perform separation of biochemical substances. A sample must be loaded onto a centrifuge by a pick-and-place device (typically a robot manipulator). Consecutive centrifuging steps may involve multiple centrifuges as well as robots, or some measure of equipment sharing. The paper proposes a unified simplified cost model for all design objectives (throughput, space utilization, process capital and operational cost) and a quantitative selection criterion to allow for an optimal automation design.