This paper seeks to analyze a CSCW (Computer Supported Cooperative Work) approach for supporting Communities of Practice; mainly we focus on discussing how awareness plays a central role for supporting knowledge sharing in a knowledge intensive community.

"To what extent can people be taught to engage in Computer Supported Cooperative Work (CSCW)?" is a question which has rarely been discussed at meetings of CSCW researchers. The present study suggests that qualitative research can contribute to the development of a curriculum for preparing nurses to work with patients who live at a distance from themselves. Building on the ethnographic research...

We investigate necessary conditions for the existence of projections of polytopes that preserve full k-skeleta. More precisely, given the combinatorics of a polytope and the dimension e of the target space, what are obstructions to the existence of a geometric realization of a polytope with the given combinatorial type such that a linear projection to e-space strictly preserves the k-skeleton. ...

Most real-world controllers are composed of proportional, integrative, and derivative signal processing blocks. The so-called PID controller was invented and patented by Callender and Stevenson in 1939. In 1942, Ziegler and Nichols developed mathematical rules for automatically selecting the parameter values for PID controllers. In their influential 1995 book, Astrom and Hagglund developed a wo...

This paper proposes the application of multiobjective genetic algorithm for optimizing the response of the PID controller for a three tank liquid level system. Liquid level system is a large-lag, time varying and non-linear system and finds a wide application in food processing, iron and steel, industrial chemical processing and other industries and the quality of control directly affects the q...

In order to get the anthropomorphic robot accurate parameters of the upper limb joint control motor, a method based on Ziegler Nichols-frequency response of the adaptive PID controller is proposed. The control circuit identifies online important critical frequency response characteristics of process object through input and output data in the normal process operation, and then the system online...

Classification of processes and tuning of the PID controllers is initiated by Ziegler and Nichols (1942). This methodology, proposed seventy years ago, is still actual and inspirational. Process dynamics characterization is defined in both the time and frequency domains by the two parameters. In the time domain, these parameters are the velocity gain Kv and dead-time L of an Integrator Plus Dea...

in this study, the slurry polymerization of ethylene over ticl4/mgcl2/alet3 was obtained. firstly, to obtain the optimum value of [al]/[ti], the effect of [al]/[ti] on polymerization rate and catalyst yield was studied. also, the effect of catalyst content on yielding, crystallization, melting point and density of product were obtained. to determine the order of reaction, the monomer pressure w...