A collaboratory, as defined by
William Wulf
William Allan Wulf (born December 8, 1939) is a computer scientist notable for his work in programming languages and compilers. Until June 2012, he was a university professor and the AT&T Professor of Engineering and Applied Sciences in the Depart ...
in 1989, is a “center without walls, in which the nation’s researchers can perform their research without regard to physical location, interacting with colleagues, accessing instrumentation, sharing data and computational resources,
ndaccessing information in
digital libraries
A digital library, also called an online library, an internet library, a digital repository, or a digital collection is an online database of digital objects that can include text, still images, audio, video, digital documents, or other digital ...
” (Wulf, 1989).
Bly (1998) refines the definition to “a
system which combines the interests of the scientific community at large with those of the
computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...
and
engineering
Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...
community to create integrated, tool-oriented computing and communication systems to support scientific collaboration” (Bly, 1998, p. 31).
Rosenberg (1991) considers a collaboratory as being an experimental and
empirical
Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and ...
research environment in which scientists work and communicate with each other to design systems, participate in collaborative science, and conduct experiments to evaluate and improve systems.
A simplified form of these definitions would describe the collaboratory as being an environment where participants make use of computing and communication technologies to access shared instruments and data, as well as to communicate with others.
However, a wide-ranging definition is provided by Cogburn (2003) who states that “a collaboratory is more than an elaborate collection of information and communications technologies; it is a new networked organizational form that also includes social processes; collaboration techniques; formal and informal communication; and agreement on norms, principles, values, and rules” (Cogburn, 2003, p. 86).
This concept has a lot in common with the notions of Interlock research, Information Routing Group and Interlock diagrams introduced in 1984.
Other meaning
The word “collaboratory” is also used to describe an open space, creative process where a group of people work together to generate solutions to complex problems.
This meaning of the word originates from the visioning work of a large group of people – including scholars, artists, consultant, students, activists, and other professionals – who worked together on the 50+20 initiative aiming at transforming management education.
In this context, by fusing two elements, “collaboration” and “laboratory”, the word “collaboratory” suggests the construction of a space where people explore collaborative innovations.
It is, as defined by Dr. Katrin Muff, “an open space for all stakeholders where action learning and action research join forces, and students, educators, and researchers work with members of all facets of society to address current dilemmas.”
The concept of the collaboratory as a creative group process and its application are further developed in the book “The Collaboratory: A co-creative stakeholder engagement process for solving complex problems”.
Examples of collaboratory events are provided on the website of the Collaboratory community as well as by
Business School Lausanne- a Swiss business school that has adopted the collaboratory method to harness
collective intelligence
Collective intelligence (CI) is shared or group intelligence (GI) that Emergence, emerges from the collaboration, collective efforts, and competition of many individuals and appears in consensus decision making. The term appears in sociobiology ...
.
Background
Problems of geographic separation are especially present in large research projects. The time and cost for traveling, the difficulties in keeping contact with other scientists, the control of experimental apparatus, the distribution of information, and the large number of participants in a research project are just a few of the issues researchers are faced with.
Therefore, collaboratories have been put into operation in response to these concerns and restrictions. However, the development and implementation proves to be not so inexpensive. From 1992 to 2000 financial budgets for scientific research and development of collaboratories ranged from
US$447,000 to
US$10,890,000 and the total use ranged from 17 to 215 users per collaboratory (Sonnenwald, 2003). Particularly higher costs occurred when software packages were not available for purchase and direct integration into the collaboratory or when requirements and expectations were not met.
Chin and Lansing (2004) state that the research and development of scientific collaboratories had, thus far, a tool-centric approach. The main goal was to provide tools for shared access and manipulation of specific software systems or scientific instruments. Such an emphasis on tools was necessary in the early development years of scientific collaboratories due to the lack of basic collaboration tools (e.g. text chat, synchronous audio or
videoconferencing
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Encyc ...
) to support rudimentary levels of communication and interaction. Today, however, such tools are available in off-the-shelf software packages such as
Microsoft NetMeeting
Microsoft NetMeeting is a discontinued VoIP and multi-point videoconferencing client included in many versions of Microsoft Windows (from Windows 95 OSR2 to Windows Vista). It uses the H.323 protocol for videoconferencing, and is interoperable w ...
,
IBM Lotus Sametime,
Mbone
Mbone (short for "multicast backbone") was an experimental backbone and virtual network built on top of the Internet for carrying IP multicast traffic on the Internet. It was developed in the early 1990s and required specialized hardware and so ...
Videoconferencing
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Encyc ...
(Chin and Lansing, 2004). Therefore, the design of collaboratories may now move beyond developing general communication mechanisms to evaluating and supporting the very nature of collaboration in the scientific context (Chin & Lansing, 2004).
The evolution of the collaboratory
As stated in Chapter 4 of the 50+20
"Management Education for the World" book,
"the term collaboratory was first introduced in the late 1980s to address problems of geographic separation in large research projects related to travel time and cost, difficulties in keeping contact with other scientists, control of experimental apparatus, distribution of information, and the large number of participants. In their first decade of use, collaboratories were seen as complex and expensive information and communication technology (ICT) solutions supporting 15 to 200 users per project, with budgets ranging from 0.5 to 10 million USD. At that time, collaboratories were designed from an ICT perspective to serve the interests of the scientific community with tool-oriented computing requirements, creating an environment that enabled systems design and participation in collaborative science and experiments.
The introduction of a user-centered approach provided a first evolutionary step in the design philosophy of the collaboratory, allowing rapid prototyping and development circles. Over the past decade the concept of the collaboratory expanded beyond that of an elaborate ICT solution, evolving into a “new networked organizational form that also includes social processes, collaboration techniques, formal and informal communication, and agreement on norms, principles, values, and rules”. The collaboratory shifted from being a tool-centric to a data-centric approach, enabling
data sharing
Data sharing is the practice of making data used for scholarly research available to other investigators. Many funding agencies, institutions, and publication venues have policies regarding data sharing because transparency and openness are consid ...
beyond a common repository for storing and retrieving shared data sets. These developments have led to the evolution of the collaboratory towards a globally distributed knowledge work that produces intangible goods and services capable of being both developed and distributed around the world using traditional ICT networks.
Initially, the collaboratory was used in scientific research projects with variable degrees of success. In recent years, collaboratory models have been applied to areas beyond scientific research and the national context. The wide acceptance of collaborative technologies in many parts of the world opens promising opportunities for international cooperation in critical areas where societal stakeholders are unable to work out solutions in isolation, providing a platform for large multidisciplinary teams to work on complex global challenges.
The emergence of open-source technology transformed the collaboratory into its next evolution. The term open-source was adopted by a group of people in the free software movement in Palo Alto in 1998 in reaction to the source code release of the Netscape Navigator browser. Beyond providing a pragmatic methodology for free distribution and access to an end product's design and implementation details, open-source represents a paradigm shift in the philosophy of collaboration. The collaboratory has proven to be a viable solution for the creation of a virtual organization. Increasingly, however, there is a need to expand this virtual space into the real world. We propose another paradigm shift, moving the collaboratory beyond its existing ICT framework to a methodology of collaboration beyond the tool- and data-centric approaches, and towards an issue-centered approach that is transdisciplinary in nature."
Characteristics and considerations
A distinctive characteristic of collaboratories is that they focus on data collection and analysis. Hence the interest to apply collaborative technologies to support data sharing as opposed to tool sharing. Chin and Lansing (2004) explore the shift of collaboratory development from traditional tool-centric approaches to more data-centric ones, to effectively support data sharing. This means more than just providing a common repository for storing and retrieving shared
data set A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the d ...
s. Collaboration, Chin and Lansing (2004) state, is driven both by the need to share data and to share knowledge about data. Shared data is only useful if sufficient context is provided about the data such that collaborators may comprehend and effectively apply it. It is therefore imperative, according to Chin and Lansing (2004), to know and understand how data sets relate to aspects of overall data space, applications, experiments, projects, and the scientific community, identifying the critical features or properties among which we can mention:
* General data set properties (owner, creation data, size, format);
* Experimental properties (conditions of the scientific experiment that generated that data);
* Data
provenance
Provenance (from the French ''provenir'', 'to come from/forth') is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art but is now used in similar senses i ...
(relationship with previous versions);
* Integration (relationship of data subsets within the full data set);
* Analysis and interpretation (notes, experiences, interpretations, and knowledge produced)
* Scientific organization (scientific classification or hierarchy);
* Task (research task that generated or applies the data set);
* Experimental process (relationship of data and tasks to the overall process);
* User community (application of data set to different users).
Henline (1998) argues that communication about experimental data is another important characteristic of a collaboratory. By focusing attention on the dynamics of information exchange, the study of Zebrafish Information Network Project (Henline, 1998) concluded that the key challenges in creating a collaboratory may be social rather than technical. “A successful system must respect existing social conventions while encouraging the development of analogous mechanisms within the new electronic forum” (Henline, 1998, p. 69). Similar observations were made in the
Computer-supported collaborative learning
Computer-supported collaborative learning (CSCL) is a pedagogical approach wherein learning takes place via social interaction using a computer or through the Internet. This kind of learning is characterized by the sharing and construction of know ...
(CSCL) case study (Cogburn, 2003). The author (Cogburn, 2003) is investigating a collaboratory established for researchers in education and other related domains from
United States of America
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territor ...
and southern
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. The main finding was that there have been important intellectual contributions on both sides, although the context was that of a developed country working together with a developing one and there have been social as well as cultural barriers. He further develops the idea that a successful CSCL would need to draw the best lessons learned on both sides in
computer-mediated communication
Computer-mediated communication (CMC) is defined as any human communication that occurs through the use of two or more electronic devices. While the term has traditionally referred to those communications that occur via computer-mediated forma ...
(CMC) and
computer-supported cooperative work (CSCW).
Sonnenwald (2003) conducted seventeen interviews with scientists and revealed important considerations. Scientists expect a collaboratory to “support their strategic plans; facilitate management of the scientific process; have a positive or neutral impact on scientific outcomes; provide advantages and disadvantages for scientific task execution; and provide personal conveniences when collaborating across distances” (Sonnenwald, 2003, p. 68). Many scientists looked at the collaboratory as means to achieve strategic goals that were organizational and personal in nature. Other scientists anticipated that the scientific process would speed up when they had access to the collaboratory.
Design philosophy
Finholt (1995), based on the case studies of the Upper Atmospheric Research Collaboratory (UARC) and the Medical Collaboratory, establishes a design philosophy: a collaboratory project must be dedicated to a
user-centered design
User-centered design (UCD) or user-driven development (UDD) is a framework of process (not restricted to interfaces or technologies) in which usability goals, user characteristics, environment, tasks and workflow of a product, service or proc ...
(UCD) approach. This means a commitment to develop software in programming environments that allow rapid prototyping, rapid development cycles (Finholt, 1995). A consequence of the
user-centered design
User-centered design (UCD) or user-driven development (UDD) is a framework of process (not restricted to interfaces or technologies) in which usability goals, user characteristics, environment, tasks and workflow of a product, service or proc ...
in the collaboratory is that the system developers must be able to distinguish when a particular system or modification has positive impact on users’ work practices. An important part of obtaining this understanding is producing an accurate picture of how work is done prior to the introduction of technology. Finholt (1995) explains that
behavioral scientists had the task of understanding the actual work settings for which new information technologies were developed. The goal of a
user-centered design
User-centered design (UCD) or user-driven development (UDD) is a framework of process (not restricted to interfaces or technologies) in which usability goals, user characteristics, environment, tasks and workflow of a product, service or proc ...
effort was to inject those observations back into the design process to provide a baseline for evaluating future changes and to illuminate productive directions for prototype development (Finholt, 1995).
A similar viewpoint is expressed by Cogburn (2003) who relates the collaboratory to a globally distributed
knowledge work, stating that
human-computer interaction (HCI) and
user-centered design
User-centered design (UCD) or user-driven development (UDD) is a framework of process (not restricted to interfaces or technologies) in which usability goals, user characteristics, environment, tasks and workflow of a product, service or proc ...
(UCD) principles are critical for organizations to take advantage of the opportunities of
globalization
Globalization, or globalisation (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-ise, -ize (-isation, -ization), see spelling differences), is the process of foreign relation ...
and the emergence of an
Information society
An information society is a society where the usage, creation, distribution, manipulation and integration of information is a significant activity. Its main drivers are information and communication technologies, which have resulted in rapid info ...
. He (Cogburn, 2003) refers to
distributed knowledge
In multi-agent system research, distributed knowledge is all the knowledge that a community of agents possesses and might apply in solving a problem. Distributed knowledge is approximately what "a wise man knows" or what someone who has complete ...
work as being a set of “economic activities that produce intangible goods and services
�� capable of being both developed and distributed around the world using the global information and communication networks” (Cogburn, 2003, p. 81). Through the use of these global information and communications networks, organizations are able to take part in globally disarticulated production, which means they can locate their research and development facilities almost anywhere in the world, and engineers can collaborate across time zones, institutions and national boundaries.
Evaluation
Meeting expectations is a factor that influences adoption of innovations, including scientific collaboratories. Some of the collaboratories implemented thus far have not been entirely successful. The Mathematics and Computer Science Division of Argonne National Laboratory, Waterfall Glen collaboratory (Henline, 1998) is an illustrative example. This collaboratory had its shares of problems. There have been the occasional technical and social disasters, but most importantly it did not meet all of the collaboration and interaction requirements.
The vast majority of the evaluations performed thus far are concentrating mainly on the usage statistics (e.g. total number of members, hours of use, amount of data communicated) or on the immediate role in the production of traditional scientific outcomes (e.g. publications and patents). Sonnenwald (2003), however, argues that we should rather look for longer-term and intangible measures such as new and continued relationship among scientists, and subsequent, longer-term creation of new knowledge.
Regardless of the criteria used for evaluation, we must focus on understanding the expectations and requirements defined for a collaboratory. Without such understanding a collaboratory runs the risk of not being adopted.
Success factors
Olson, Teasley, Bietz, and Cogburn (2002) ascertain some of the success factors of a collaboratory. They are: collaboration readiness, collaboration infrastructure readiness, and collaboration technology readiness.
Collaboration readiness is the most basic pre-requisite for an effective collaboratory, according to Olson, Teasley, Bietz, and Cogburn (2002). Often the critical component to collaboration readiness is based on the concept of “working together in order to achieve a science goal” (Olson, Teasley, Bietz, & Cogburn, 2002, p. 46).
Incentive
In general, incentives are anything that persuade a person to alter their behaviour. It is emphasised that incentives matter by the basic law of economists and the laws of behaviour, which state that higher incentives amount to greater levels of ...
s to collaborate, shared principles of collaboration, and experience with the elements of collaboration are also crucial. Successful interaction between users requires a certain amount of common ground. Interactions require a high degree of trust or negotiation, especially when they involve areas where there is a
cultural difference
Cultural diversity is the quality of diverse or different cultures, as opposed to monoculture, the global monoculture, or a homogenization of cultures, akin to cultural evolution. The term "cultural diversity" can also refer to having different c ...
. “Ethical norms tend to be culturally specific, and negotiations about ethical issues require high levels of trust” (Olson, Teasley, Bietz, & Cogburn, 2002, p. 49).
When analyzing the collaboration infrastructure readiness Olson, Teasley, Bietz, and Cogburn (2002) state that modern collaboration tools require adequate infrastructure to operate properly. Many off-the-shelf applications will run effectively only on state-of-the-art workstations. An important piece of the infrastructure is the technical support necessary to ensure version control, to get participants registered, and to recover in case of disaster. Communications cost is another element which can be critical for collaboration infrastructure readiness (Olson, Teasley, Bietz, & Cogburn, 2002). Pricing structures for network connectivity can affect the choices that users will make and therefore have an effect on the collaboratory's final design and implementation.
Collaboration technology readiness, according to Olson, Teasley, Bietz, and Cogburn (2002), refers to the fact that collaboration does not involve only technology and infrastructure, but also requires a considerable investment in training. Thus, it is essential to assess the state of technology readiness in the community to ensure success. If the level is too primitive more training is required to bring the users’ knowledge up-to-date.
Examples
Biological Sciences Collaboratory
A comprehensively described example of a collaboratory, the Biological Sciences Collaboratory (BSC) at the Pacific Northwest National Laboratory (Chin & Lansing, 2004), enables the sharing and analysis of biological data through
metadata capture,
electronic laboratory notebooks, data organization views, data
provenance
Provenance (from the French ''provenir'', 'to come from/forth') is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art but is now used in similar senses i ...
tracking, analysis notes, task management, and scientific
workflow management
A workflow consists of an orchestrated and repeatable pattern of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a sequence of ...
. BSC supports various data formats, has data translation capabilities, and can interact and exchange data with other sources (external
database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spa ...
s, for example). It offers subscription capabilities (to allow certain individuals to access data) and verification of identities, establishes and manages permissions and privileges, and has data
encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can dec ...
capabilities (to ensure secure
data transmission
Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point o ...
) as part of its security package.
BSC also provides a data
provenance
Provenance (from the French ''provenir'', 'to come from/forth') is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art but is now used in similar senses i ...
tool and a data organization tool. These tools allow a
hierarchical tree
A hierarchy (from Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important ...
to display the historical lineage of a data set. From this tree-view the scientist may select a particular
node
In general, a node is a localized swelling (a "knot") or a point of intersection (a vertex).
Node may refer to:
In mathematics
* Vertex (graph theory), a vertex in a mathematical graph
* Vertex (geometry), a point where two or more curves, line ...
(or an entire branch) to access a specific version of the data set (Chin & Lansing, 2004).
The
task management
Task management is the process of managing a task through its life cycle. It involves planning, testing, tracking, and reporting. Task management can help either individual achieve goals, or groups of individuals collaborate and share knowledg ...
provided by BSC allows users to define and track tasks related to a specific experiment or project. Tasks can have deadlines assigned, levels of priority, and dependencies. Tasks can also be
queried and various reports produced. Related to
task management
Task management is the process of managing a task through its life cycle. It involves planning, testing, tracking, and reporting. Task management can help either individual achieve goals, or groups of individuals collaborate and share knowledg ...
, BSC provides
workflow management
A workflow consists of an orchestrated and repeatable pattern of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a sequence of ...
to capture, manage, and supply standard paths of analyses. The scientific workflow may be viewed as process templates that captures and semi-automate the steps of an analysis process and its encompassing data sets and tools (Chin & Lansing, 2004).
BSC provides project collaboration by allowing scientists to define and manage members of their group. Security and authentication mechanisms are therefore applied to limit access to project data and applications. Monitoring capability allows for members to identify other members that are online working on the project (Chin & Lansing, 2004).
BSC offers community collaboration capabilities: scientists may publish their data sets to a larger community through the
data portal. Notifications are in place for scientists interested in a particular set of data - when that data changes, the scientists get notification via email (Chin & Lansing, 2004).
Diesel Combustion Collaboratory
Pancerella, Rahn, and Yang (1999) analyzed the Diesel Combustion Collaboratory (DCC) which was a problem-solving environment for combustion research. The main goal of DCC was to make the information exchange for the combustion researchers more efficient. Researchers would collaborate over the Internet using various DCC tools. These tools included “a distributed execution management system for running combustion
models on widely distributed computers (
distributed computing
A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...
), including
supercomputers
A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second (FLOPS) instead of million instructions ...
; web accessible data archiving capabilities for sharing graphical experimental or modeling data;
electronic notebooks and shared
workspace
Workspace is a term used in various branches of engineering and economic development.
Business development
Workspace refers to small premises provided, often by local authorities or economic development agencies, to help new businesses to estab ...
s for facilitating collaboration; visualization of
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combust ...
data; and
videoconferencing
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Encyc ...
and
data conferencing
Data conferencing refers to a communication session among two or more participants sharing computer data in real time. Interaction and presentation devices such as a screen, keyboard, mouse, camera, etc. can be shared or be able to control each ot ...
among researchers at remote sites” (Pancerella, Rahn, & Yang, 1999, p. 1).
The collaboratory design team defined the requirements to be (Pancerella, Rahn, & Yang, 1999):
* Ability share graphical data easily;
* Ability to discuss
modeling strategies and exchange model descriptions;
* Archiving collaborative information;
* Ability to run combustion models at widely separated locations;
* Ability to analyze experimental data and
modeling results in a web-accessible format;
*
Videoconference
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Ency ...
and group meetings capabilities.
Each of these requirements had to be done securely and efficiently across the Internet. Resources availability was a major concern because many of the chemistry simulations could run for hours or even days on high-end workstations and produce
Kilobytes
The kilobyte is a multiple of the unit byte for digital information.
The International System of Units (SI) defines the prefix '' kilo'' as 1000 (103); per this definition, one kilobyte is 1000 bytes.International Standard IEC 80000-13 Quantit ...
to
Megabytes
The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB. The unit prefix ''mega'' is a multiplier of (106) in the International System of Units (SI). Therefore, one megabyte is one million bytes ...
of data sets. These data sets had to be visualized using simultaneous
2-D plots of multiple variables (Pancerella, Rahn, & Yang, 1999).
The deployment of the DCC was done in a phased approach. The first phase was based on iterative development, testing, and deployment of individual collaboratory tools. Once collaboratory team members had adequately tested each new tool, it was deployed to combustion researchers. The deployment of the infrastructure (
videoconferencing
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Encyc ...
tools,
multicast
In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused wit ...
<