Is It Rational to Assume that Infants Imitate Rationally? A Theoretical Analysis and Critique

It has been suggested that preverbal infants evaluate the efficiency of others' actions (by applying a principle of rational action) and that they imitate others' actions rationally. The present contribution presents a conceptual analysis of the claim that preverbal infants imitate rationally. It shows that this ability rests on at least three assumptions: that infants are able to perceive others' action capabilities, that infants reason about and conceptually represent their own bodies, and that infants are able to think counterfactually. It is argued that none of these three abilities is in place during infancy. Furthermore, it is shown that the idea of a principle of rational action suffers from two fallacies. As a consequence, is it suggested that it is not rational to assume that infants imitate rationally. Copyright (C) 2012 S. Karger AG, Base

The Jefferson Lab Trigger Supervisor System

The authors discuss the design and performance of a Trigger Supervisor System for use in nuclear physics experiments at Jefferson Lab. They also discuss the enhanced features of a new Trigger Supervisor Module now under construction

Fast transfer of shared data

The Event Transfer system enables its users to produce events (data) and share them with other users by utilizing shared memory on either Solaris or Linux-based computers. Its design emphasizes speed, reliability, ease of use, and recoverability from crashes. In addition to fast local operation, the ET system allows network transfer of events. Using multi-threaded code based on POSIX threades and mutexes, a successful implementation was developed which allowed passing events over 500 kHz on a 4 cpu Sun workstation and 150 kHz on a dual cpu PC

CODA performance in the real world

The most ambitious implementation of the Jefferson Lab data acquisition system (CODA) to date is for the CLAS spectrometer in Experimental Hall B. CLAS has over 40,000 instrumented channels and uses up to 30 front-end (FASTBUS/VME) crates in the DAQ subsystem. During the initial experiments the authors found that performance of the fully instrumented DAQ system did not scale as expected based on single point to point benchmarks. Over the past year the authors have been able to study various performance bottlenecks in the CLAS DAQ system including front-end real time performance, switched 100BaseT Ethernet data transport, and online data distribution and recording. Performance tuning was necessary for components on both real time (VxWorks) and UNIX (Solaris) operating systems. In addition, a new efficient Event Transfer System (ET) was developed to provide faster online monitoring while having minimal impact on data throughput to storage. They discuss these issues and efforts to overcome the real world problems associated with running a high performance DAQ system on a variety of commercial hardware and software