Friday, March 14, 2008

Broadcast Search

A broadcast search is issued by a network node because a directed search using database information has failed or there is no database information for the requested resource. A broadcast search does not use database information about the location of a requested LU to propagate the search. Instead, a broadcast search is sent to every adjacent network node at the same time. Each of the adjacent network nodes then forwards the broadcast search to all other adjacent network nodes, and so forth. After propagating a broadcast search to all adjacent network nodes, each network node also searches all its client end nodes to determine if the target LU resides within the domain of the network node.
This process allows the entire network to be searched. When the search reaches the network node serving the destination resource, that node sends back a positive reply to the first search request it receives.
In Figure 1, LUA on ENA wants to start a session with LUB on ENB.
Figure 1. Broadcast search - stage 1










ENA sends a directed search to its network node server (NN1). Because the directory database of NN1 has no information about LUB, NN1 sends a network broadcast search to all end nodes served by NN1. If LUB is not located in the NN1 local domain, the broadcast search is propagated at the same time to all adjacent network nodes.
After propagating the broadcast search, network nodes search local node and served end nodes.


Figure 2. Broadcast search - propagating to served end nodes












Since LUB is located in ENB, ENB sends a positive reply to the broadcast search request. The reply is returned along the same path as the request. The directory database in NN4 and NN1 is updated with the information about the locations of both LUB and LUA.

Tuesday, March 04, 2008

The Value of Openness in Scientific Problem Solving

Karim R. Lakhani
Lars Bo Jeppesen
Peter A. Lohse
Jill A. Panetta

Copyright © 2007 by Karim R. Lakhani, Lars Bo Jeppesen, Peter A. Lohse and Jill A. Panetta


Openness and unrestricted information sharing amongst scientists have been identified as
institutional norms that are critical to scientific progress [1] and the key distinguishing
features that separate the scientific community from other spheres of activity [2].
However, empirical studies of the behavior of scientists have shown that career [3],
publication priority [4], intellectual property and financial concerns [5,6] often trump
openness to the potential detriment of overall scientific advancement. For example, 47
per cent of academic geneticists who asked other researchers for additional information
or materials regarding published research reported that at least one of their requests had
been denied in the preceding three years [5]. Another study showed that only 14 per cent
of experimental biologists were willing to talk openly about their current research with
other colleagues [7]. The result of this lack of openness is that scientific problem solving
activity is constrained and fails to adequately leverage the larger accumulation of
knowledge amongst the wider scientific community.
More recently, free and open source software communities have demonstrated that
actually practicing the norms of openness and information sharing in a peer-production
setting can result in the creation of complex technological products that approach, and
sometimes rival, the scope and quality of similar products produced by proprietary efforts
[8,9]. The robustness of open information sharing and collective production has been
demonstrated in fields as diverse as the creation of encyclopedia entries on sciencerelated
topics [10], bioinformatics [11] and cultural products [12]. These initiatives have
shown that openness and collaboration before, during, and after problem solving efforts
can harness the knowledge of many towards creating unique solutions.
4
Here we show that the opening up of information about difficult and unsolved scientific
problems to a large group of unknown “outsiders” can be an effective problem solving
strategy. Most problem solvers extensively use prior experience and knowledge in their
attempts at solving problems, resulting in a “local search” of the potential solution space
[13,14]. Opening up the search process and broadcasting problem information to
outsiders can alleviate the negative effects of local search. We call this problem solving
approach “broadcast search.” The premise of broadcast search is the central insight that
knowledge is unequally and widely distributed in society [15] and that the locus of
innovation and problem solving shifts to where knowledge is stickiest (i.e. difficult to
access or move)[16].
Our study finds that the broadcast of problem information to outside scientists results in a
29.5% resolution rate for scientific problems that had previously remained unsolved
inside the R & D laboratories of well-known science-driven firms. Problem solving
success was associated with the ability to attract specialized scientists with diverse
scientific interests. Furthermore, successful solvers created solutions to problems that
were on the boundary or outside of their fields of expertise, showing that openness in
science can trigger the transfer and transformation of knowledge from one scientific field
to other. We also found that solvers mainly relied on information from previously
developed solutions when attempting to solve broadcast problems, indicating a relatively
efficient knowledge transfer mechanism. Finally, successful solvers were motivated to
engage in problem solving effort by either intrinsic motivations or financial reward.

Read more @ http://www.hbs.edu/research/pdf/07-050.pdf