Saturday, November 22, 2008
Week 11: Problem Based Learning and Simulation Games
Amit Deshpande at http://www.amit-deshpande.com/2008/10/simulation-games-4-problem-based.html provides a nice concise distinction between problem-based learning and simulation game based learning. Amit's comments describe simulation game base learning as having problem based learning as a subset but then with characteristics of its own. What makes these approaches appropriate for learning is that they have attributes of constructivism - active, collaborative, and learner centered. The simulation game approach also has the instructor as a facilitator rather than a teacher. Also, where the problem based approach has self assessment at the end of a learning area, the game based approach gives the learner ongoing incentive to get higher scores through more study and reading. Games also have increasingly complex graphics and multimedia displays which aids visual learners. In addition, games usually have help capability, allowing the learner to solve problems encountered during the learning process without extensive help from the instructor. Finally, the games allow the learner to try different strategies and get immediate feedback of the results of those decisions.
Week 10: Learning Objects and Constructivism
Learning objects are an interesting approach by instructional designers to create flexible development environments for the creation of course materials. Using learning objects, the content for a course is made up of small pieces that can be reused, split apart into yet smaller pieces, put together into other larger pieces, and generally reorganized in any way that is needed for course creation. Teaching has shown me that students learn best when they are actively engaged in the learning process. When looking at learning objects, I wonder how they can be used to create a constructivist learning environment. According to Bannan-Ritland, Dabbagh, & Murphy (2001), in order for learning objects to support a constructivist learning environment, they must support the storing of learner-created content and allow for this content to be organized in a way that it can be searched for later use. Availablity of learner-created content allows learners to be involved in the creative process of learning.
Washabaugh (2003) tells us that learning can be divided into two general areas, that of knowledge development where the learner accumulates facts and information, and the area of understanding where the knowledge learned is used in ways that lead to an understanding of a problem and the issues involved in solving that problem. Learning objects seem to focus on the knowledge area and not on the understanding area. In order to support a constructivist learning environment, Washabaugh suggests learning objects engage the learner, provide interactivity, be student-centered, and be socially interactive providing collaboration and team work. Washabaugh sees these learning objects as being like computer games where learners make decisions and see the ramifications of their decisions.
Despite the flexible nature of small pieces that can be reorganzied, it seems that current learning objects provide a structure that is too rigid for student centered learning, focusing more on a teacher-led or computer-led approach based on a fixed plan. There is hope for a change to this with the focus moving to the creation and storing of learner content (which could be learning objects themselves), interactivity which includes team processes and collaboration, and the concept of games and decision processing.
References
Bannan-Ritland, B., Dabbagh, N., & Murphy, K. (2001). Learning object systems as constructivist learning environments: Related assumptions, theories and applications. In D. Wiley (Ed.), The Instructional Use of Learning Objects. Association of Educational Communications and Technology.
Washabaugh, M. (2003). Learning objects in a constructivist curriculum. Teaching With Technology Today, 9(6). Retrieved on November 16, 2008, from http://www.uwsa.edu/ttt/articles/washabaugh.htm
Washabaugh (2003) tells us that learning can be divided into two general areas, that of knowledge development where the learner accumulates facts and information, and the area of understanding where the knowledge learned is used in ways that lead to an understanding of a problem and the issues involved in solving that problem. Learning objects seem to focus on the knowledge area and not on the understanding area. In order to support a constructivist learning environment, Washabaugh suggests learning objects engage the learner, provide interactivity, be student-centered, and be socially interactive providing collaboration and team work. Washabaugh sees these learning objects as being like computer games where learners make decisions and see the ramifications of their decisions.
Despite the flexible nature of small pieces that can be reorganzied, it seems that current learning objects provide a structure that is too rigid for student centered learning, focusing more on a teacher-led or computer-led approach based on a fixed plan. There is hope for a change to this with the focus moving to the creation and storing of learner content (which could be learning objects themselves), interactivity which includes team processes and collaboration, and the concept of games and decision processing.
References
Bannan-Ritland, B., Dabbagh, N., & Murphy, K. (2001). Learning object systems as constructivist learning environments: Related assumptions, theories and applications. In D. Wiley (Ed.), The Instructional Use of Learning Objects. Association of Educational Communications and Technology.
Washabaugh, M. (2003). Learning objects in a constructivist curriculum. Teaching With Technology Today, 9(6). Retrieved on November 16, 2008, from http://www.uwsa.edu/ttt/articles/washabaugh.htm
Week 12: Lessons Learned
Some of the lesssons I have learned in our Computer Technology and Multimedia course include the power of software that provides discussion forums, wiki's for collaboration, blogs for making student knowledge, research, and views available to all on the Internet, podcasts for making course information available, and synchronous communications through video conferencing for remote course capabilities.
Discussion forums have been a part of this course and have given hands-on experience with asynchronous communications. I have also gained experience with the use of wiki's and will have my students use these to create and coordinate various document creation exercises. I will also have students in other courses use blogs to make their views available to all on the Internet in order to perhaps get feedback from people outside the course. After having gained experience in creating a video presentation, I will finally get around to creating podcasts of my course content and make it availabe to students for review. I also hope to be involved in the creation of remote classrooms through the use of video conferencing to provide a synchronous environment for our students.
Discussion forums have been a part of this course and have given hands-on experience with asynchronous communications. I have also gained experience with the use of wiki's and will have my students use these to create and coordinate various document creation exercises. I will also have students in other courses use blogs to make their views available to all on the Internet in order to perhaps get feedback from people outside the course. After having gained experience in creating a video presentation, I will finally get around to creating podcasts of my course content and make it availabe to students for review. I also hope to be involved in the creation of remote classrooms through the use of video conferencing to provide a synchronous environment for our students.
Thursday, November 20, 2008
Week 12: Skype Comment
My experiences with skype have been very positive. I will use it next semester as a tool for students to collaborate on team design projects. Skype does not have a steep learning curve and is very intuitive in its use. A very efficient environment will be created by using a wiki to control the development of the design documents and using skype to discuss designs and changes to designs. Students in this course are adults who work full-time during the day and find it difficult to meet as a team face-to-face outside of the normal class meetings. Meeting on skype will solve this problem. The ability to bring multiple people into the conversation is a major plus.
Week 9: Stakeholder and Designer Effect on LMS Software
I have found that when designing a software system, the analysis phase is the most interesting. This phase of a development project is when the needs of all the stakeholders are determined. It is these needs that then determine the direction of the project, and ultimately what the final software system will look like. This sounds simple enough. What could possibly go wrong as long as we find and handle all of the needs? Well, sometimes the needs of the stakeholders conflict. For example, someone financing the project is more concerned about cost than the user who wants a capability that will make him more effective at his job. Then there is the security officer who wants to be certain that solid security is built into to software which may make user access more cumbersome. Ultimately, the find product becomes a compromise between all of the stakeholders needs.
I began to think about this again when I came across a blog by David Jones called “The dissonance gap in systems and LMS evaluations” at http://davidtjones.wordpress.com/2008/11/17/the-dissonance-gap-in-systems-and-lms-evaluations/. LMS stands for Learning Management System. In his blog entry he takes the stakeholder needs idea a step further in that he says that designers (all those involved in designing a system) are affected by their world view that has been created by their past experiences. This world view then will affect the design of the system. The “dissonance” or difference between what the software will support and how you want to use the software can have an effect on your ability to use the final software product effectively. The wider the gap, the less likely it is that you can effectively use the product. Blackboard is used as an example of how groups of users are restricted in some ways as to how they can be organized into discussion groups. This is an example of the “dissonance gap” created by the design (and the designers) between the Blackboard software and the users.
What can you do about it? First, determine how you expect to use the software. What are all of the scenarios that describe how it will be used? Then, does Blackboard, or whichever LMS software you are evaluating, support those scenarios. If not, can you work within its limitations, or do you need to look at another LMS product?
I began to think about this again when I came across a blog by David Jones called “The dissonance gap in systems and LMS evaluations” at http://davidtjones.wordpress.com/2008/11/17/the-dissonance-gap-in-systems-and-lms-evaluations/. LMS stands for Learning Management System. In his blog entry he takes the stakeholder needs idea a step further in that he says that designers (all those involved in designing a system) are affected by their world view that has been created by their past experiences. This world view then will affect the design of the system. The “dissonance” or difference between what the software will support and how you want to use the software can have an effect on your ability to use the final software product effectively. The wider the gap, the less likely it is that you can effectively use the product. Blackboard is used as an example of how groups of users are restricted in some ways as to how they can be organized into discussion groups. This is an example of the “dissonance gap” created by the design (and the designers) between the Blackboard software and the users.
What can you do about it? First, determine how you expect to use the software. What are all of the scenarios that describe how it will be used? Then, does Blackboard, or whichever LMS software you are evaluating, support those scenarios. If not, can you work within its limitations, or do you need to look at another LMS product?
Sunday, October 26, 2008
Week 8: Benefits of Wireless Technology in Higher Education
The use of mobile wireless technology in higher education generates questions regarding what advantages this new technology generates. Studies (Kim, Mims, & Holmes, 2006) talk about the efficiency and effectiveness in teaching and learning created by mobile technology. But what does this mean? Certainly we can be more mobile, but how does this benefit learning? First, mobile wireless technology lets us communicate more easily. This allows us to collaborate more easily with other students and with faculty. Discussing topics of study with others allows us to come in contact with other ways of viewing a problem and its possible solutions. The phrase “two heads are better than one” can be expanded through collaboration to “many heads are better than one”. This collaboration can be real time or asynchronously, whichever is more convenient at the time.
Second, creating documents in digital form allows us to transmit and share information more quickly. We can take notes online, create reports, and transmit this information to other students and faculty because it is not in hardcopy form. Third, students see the importance of time management as learning and other environments become more and more seamless. Fourth, there is faster access to information as much of it is online. We can even read books online. We have access to this information through a wireless device; we do not have to visit a library. And fifth, we can take courses completely online, saving travel time and simplifying scheduling. In addition, there are indirect benefits to wireless technologies. We can have Internet access in areas where wired technologies can not economically and otherwise provide access. Within classrooms and on campuses the lack of wiring allows more flexibility for meeting locations.
This technology is in its infancy. As the technology matures and we become more comfortable with it, we will find more uses for it and more benefits.
Kim, S. H., Mims, C., & Holmes, K. P. (2006). An introduction to current trends and benefits of mobile wireless technology use in higher education. AACE Journal, 14(1), 77-100.
Second, creating documents in digital form allows us to transmit and share information more quickly. We can take notes online, create reports, and transmit this information to other students and faculty because it is not in hardcopy form. Third, students see the importance of time management as learning and other environments become more and more seamless. Fourth, there is faster access to information as much of it is online. We can even read books online. We have access to this information through a wireless device; we do not have to visit a library. And fifth, we can take courses completely online, saving travel time and simplifying scheduling. In addition, there are indirect benefits to wireless technologies. We can have Internet access in areas where wired technologies can not economically and otherwise provide access. Within classrooms and on campuses the lack of wiring allows more flexibility for meeting locations.
This technology is in its infancy. As the technology matures and we become more comfortable with it, we will find more uses for it and more benefits.
Kim, S. H., Mims, C., & Holmes, K. P. (2006). An introduction to current trends and benefits of mobile wireless technology use in higher education. AACE Journal, 14(1), 77-100.
Thursday, October 16, 2008
Week 7: Aysnchronous or Synchronous Learning?
Matt Crosslin at http://www.edugeekjournal.com/blog.php?id=198 discusses a few advantages and disadvantages of asynchronous and synchronous online learning. He prefers asynchronous learning with which I happen to agree but I think he has taken his position too far. He states that video conferencing (synchronous) has no place in online learning. But then he states that it may appeal to some people. What I think he should have said is that everyone learns differently and some people prefer not only online synchronous lectures and presentations but may even prefer in-class face-to-face meetings. There is a need for all types of learning environments, not just one. Why can’t synchronous communication as well as synchronous be available?
Matt makes a couple of good points. He wants active learning. He wants to interact with other students. Certainly video conferencing tends to be mostly lecture format but it depends on the quality of the videoconferencing technology being used. I have seen some videoconferencing where you felt you were in the same room as the speaker and you could ask questions and get immediate answers. Here Matt contends that synchronous meetings tend to be short (1 or 2 hours) and there is not enough time to think about questions and form good answers. This may be true, but if you do have a question, you can get an answer right now. Matt also contends that some students dominate class time and others have to sit back quietly and asynchronous communication precludes this from happening. On this Matt is correct. A shy person tends to be more outgoing in an asynchronous mode. However, asynchronous communications can be lonely to some, and a shy person can be very lonely in an asynchronous environment.
The bottom line is that we are all different and all forms of communication and learning need to be available to all of us so that we can all learn effectively in our own ways.
Matt makes a couple of good points. He wants active learning. He wants to interact with other students. Certainly video conferencing tends to be mostly lecture format but it depends on the quality of the videoconferencing technology being used. I have seen some videoconferencing where you felt you were in the same room as the speaker and you could ask questions and get immediate answers. Here Matt contends that synchronous meetings tend to be short (1 or 2 hours) and there is not enough time to think about questions and form good answers. This may be true, but if you do have a question, you can get an answer right now. Matt also contends that some students dominate class time and others have to sit back quietly and asynchronous communication precludes this from happening. On this Matt is correct. A shy person tends to be more outgoing in an asynchronous mode. However, asynchronous communications can be lonely to some, and a shy person can be very lonely in an asynchronous environment.
The bottom line is that we are all different and all forms of communication and learning need to be available to all of us so that we can all learn effectively in our own ways.
Saturday, October 4, 2008
Open-Ended Learning and Problem Solving
Bill Robertson has a blog at http://pensamientosdesantiagodechile.blogspot.com/2008/10/que-es-su-problema-what-is-your-problem.html. In a recent posting he describes the importance of having problem solving skills. After all, as he puts it, life is full of problems. This got me thinking about our teaching methods in higher education and how many of us as faculty still hold on to the lecture method to “teach” students. This method does nothing to help students become problem solvers. I have seen so many students become stumped while working on a problem and just give up without trying solve the problem. Those students have no knowledge of any methodology to solve a problem. As Bill says, problem solving requires critical thinking skills. You have to be able to analyze and evaluate. He uses problem based learning (PBL) when he teaches. PBL requires students to take charge and think critically, and problem solve. Rather than provide information to the student, the student is actively involved in finding information, or solutions. PBL is one form of open-ended learning that puts the student in the middle of the learning process. I think this is motivating to the student. I have never found lectures to be very stimulating whether I am listening to one or giving one.
There are those who would say that student-centered learning is inefficient and takes too long. I think if all you want to do is cover the topic content then those people are right. But if you want students to understand the content and be able to apply it and be able to retain it, then the extra time needed is a small investment with a large return on that investment. We need to be more open-ended in our teaching methodologies. I have moved in that direction and have found educating students in that way to be very fulfilling as they eagerly learn as opposed to turning off a lecture and daydreaming.
There are those who would say that student-centered learning is inefficient and takes too long. I think if all you want to do is cover the topic content then those people are right. But if you want students to understand the content and be able to apply it and be able to retain it, then the extra time needed is a small investment with a large return on that investment. We need to be more open-ended in our teaching methodologies. I have moved in that direction and have found educating students in that way to be very fulfilling as they eagerly learn as opposed to turning off a lecture and daydreaming.
Sunday, September 28, 2008
Blogs and Wikis and Problem Solving
I have spent most of my adult life involved in the computer industry beginning as a computer programmer, then performing systems analysis, followed by consulting work, and finally moving into education, teaching undergraduate and graduate computer science and information technology courses. The evolution from batch processing systems to the Internet we now take for granted has been amazing. Back in the good old days, the operating system and other computer programs controlled what was happening inside a computer. The programs determined what would happen next. The programs would ask for data when they needed it. Human computer operators mounted tapes and disk drives when requested by the program. The human was subservient to the computer. Then changes began to occur.
First, programs began to appear that did not control the data that was being entered. This was the advent of the spreadsheet. A foundation program was provided which allowed users to place data of all types in cells of a spreadsheet. Then the user, using relatively simple instructions, described what the spreadsheet needed to do such as adding columns of numbers or doing statistical analyses. With these spreadsheet programs, users began to take over control of computers. Next, windows-like operating systems and applications began to appear. Instead of a program controlling what was to be done next, the user could select an icon on a screen in order to tell the computer what to do next. Now the user had even more control of the computer.
We now have the Internet. The newest applications available are called Web 2.0 tools, allowing users to connect, collaborate, publish, discuss, evaluate, negotiate, and create new knowledge on the World Wide Web. Two of the more popular tools are blogs and wikis. The popularity of these tools is astounding. According to Kevin Kelly in the August 2005 issue of Wired magazine, the number of web pages is greater than 600 billion. “In fewer than 4,000 days, we have encoded half a trillion versions of our collective story and put them in front of 1 billion people, or one-sixth of the world's population.” The growth continues unabated in 2008. What is amazing is that all of this has been created by individuals like you and me, not giant publishing houses. Through the use of blogs, wikis, and other tools, the individual is now deeply involved in knowledge creation and sharing that knowledge with others. No longer are the few experts determining what is to be published and read. Consumers are also producers of content. Kelly wonders what will happen when the number of producers surpasses the number of consumers, when people are creating blog entries, for example, but not reading. He says that is alright. He explains by saying that “the producers are the audience, the act of making is the act of watching, and every link is both a point of departure and a destination.”
In his book, The Wisdom of Crowds, James Surowiecki states that giving problems to be solved to a large and diverse enough group, the group will provide solutions that are intellectually superior in comparison to the individual expert, no matter how wise and informed he might be. Is it possible that our massive Internet of blogs, wikis, web pages, and other sites, controlled by over a billion individuals just might be the problem solving power we need to solve the complex issues currently in our global society?
First, programs began to appear that did not control the data that was being entered. This was the advent of the spreadsheet. A foundation program was provided which allowed users to place data of all types in cells of a spreadsheet. Then the user, using relatively simple instructions, described what the spreadsheet needed to do such as adding columns of numbers or doing statistical analyses. With these spreadsheet programs, users began to take over control of computers. Next, windows-like operating systems and applications began to appear. Instead of a program controlling what was to be done next, the user could select an icon on a screen in order to tell the computer what to do next. Now the user had even more control of the computer.
We now have the Internet. The newest applications available are called Web 2.0 tools, allowing users to connect, collaborate, publish, discuss, evaluate, negotiate, and create new knowledge on the World Wide Web. Two of the more popular tools are blogs and wikis. The popularity of these tools is astounding. According to Kevin Kelly in the August 2005 issue of Wired magazine, the number of web pages is greater than 600 billion. “In fewer than 4,000 days, we have encoded half a trillion versions of our collective story and put them in front of 1 billion people, or one-sixth of the world's population.” The growth continues unabated in 2008. What is amazing is that all of this has been created by individuals like you and me, not giant publishing houses. Through the use of blogs, wikis, and other tools, the individual is now deeply involved in knowledge creation and sharing that knowledge with others. No longer are the few experts determining what is to be published and read. Consumers are also producers of content. Kelly wonders what will happen when the number of producers surpasses the number of consumers, when people are creating blog entries, for example, but not reading. He says that is alright. He explains by saying that “the producers are the audience, the act of making is the act of watching, and every link is both a point of departure and a destination.”
In his book, The Wisdom of Crowds, James Surowiecki states that giving problems to be solved to a large and diverse enough group, the group will provide solutions that are intellectually superior in comparison to the individual expert, no matter how wise and informed he might be. Is it possible that our massive Internet of blogs, wikis, web pages, and other sites, controlled by over a billion individuals just might be the problem solving power we need to solve the complex issues currently in our global society?
Sunday, September 21, 2008
Adventure Learning
The description of adventure learning by Walczak (2002) is futuristic in nature, prodding us to think about where technology is leading us in the design and definition of education. Many constructivist principles are the basis for adventure learning. Alessi & Trollip (2001, pg. 32) provide a list of such principles. Adventure learning is perhaps constructivist learning supported by very high technology. For example, adventure learning facilitates knowledge construction by the learner, focuses on learning and not teaching, has the student discover rather than provide the student with answers, and describes the learning tasks as being relevant to the learner.
Where the article does not include constructivist principles is in the area of group collaboration. The article does indicate support for "group immersion education experience" but Iona seems to work only in the individual immersion education. Alessi & Trollip (2001) provide many references of research where the advantages of group cooperation and collaboration are demonstrated. Also it is questionable just how purposeful Iona's activities are. There is much student interactivity but the goals are not apparent. As Iona moves from one activity to another, the benefits of reflection may also be missing. In addition, the virtual reality aspects assume that real world complexity is expressed to its fullest, an unlikely attainment by the year 2020. Authentic real world tasks solving real world problems shows the student the complex world in which we must live and the need for complex answers.
Alessi, S. M., & Trollip, S. R. (2001). Multimedia for learning: Methods and development (3rd ed.). Boston: Allyn and Bacon.
Walczak, D. (2002). Encompassing education, pp. 60-64, In Department of Commerce. (2003). Visions 2020: Transforming education and training through advanced technologies. Government Report. Retrieved September 19, 2008 from, http://www.technology.gov/reports/TechPolicy/2020Visions.pdf
Where the article does not include constructivist principles is in the area of group collaboration. The article does indicate support for "group immersion education experience" but Iona seems to work only in the individual immersion education. Alessi & Trollip (2001) provide many references of research where the advantages of group cooperation and collaboration are demonstrated. Also it is questionable just how purposeful Iona's activities are. There is much student interactivity but the goals are not apparent. As Iona moves from one activity to another, the benefits of reflection may also be missing. In addition, the virtual reality aspects assume that real world complexity is expressed to its fullest, an unlikely attainment by the year 2020. Authentic real world tasks solving real world problems shows the student the complex world in which we must live and the need for complex answers.
Alessi, S. M., & Trollip, S. R. (2001). Multimedia for learning: Methods and development (3rd ed.). Boston: Allyn and Bacon.
Walczak, D. (2002). Encompassing education, pp. 60-64, In Department of Commerce. (2003). Visions 2020: Transforming education and training through advanced technologies. Government Report. Retrieved September 19, 2008 from, http://www.technology.gov/reports/TechPolicy/2020Visions.pdf
Serious Games: A Better CBT?
A blog item posted by Dipak Mawale at
http://dipakmawale.blogspot.com/2008/09/serious-games-and-related-concepts_19.html discusses “serious games” a strategy that can provide motivating and engaging learning experiences on computers. Alessi & Trollip (2001) describe the behavioral, cognitive, and constructivist views of learning and how they can and have been applied in CBT and WBT. I have constructivist leanings so I am interested in learning that involves the learner, where interactivity is a prime characteristic of the learning environment. Many training software packages provide the content, but in a way where the learner is a passive component in the learning (or should I say the teaching).
I have to admit that I am not very familiar with the term “serious games”. In a Google search of other sites I learned that it is using games in non-entertainment sectors. Education is certainly one of those sectors. It sounds like a strategy already being used in education called “edutainment”. Dipak points out that serious games focuses on problem solving and important elements of learning where edutainment focuses on having fun. Serious games is a strategy of using digital game technology to provide the interactivity needed by students as they construct knowledge. Dipak states that edutainment failed because its games were boring and were often nothing more than drills.
Serious games has been slow be accepted as an educational tool due to its high tech needs which had not been available. With the creation of multiplayer games, serious games now has the capability to provide powerful educational tools. More information about serious games can be found at the Serious Games Summit site at http://www.gdconf.com/conference/sgs.htm.
Alessi, S. M., & Trollip, S. R. (2001). Multimedia for learning: Methods and development (3rd ed.). Boston, MA: Allyn and Bacon.
http://dipakmawale.blogspot.com/2008/09/serious-games-and-related-concepts_19.html discusses “serious games” a strategy that can provide motivating and engaging learning experiences on computers. Alessi & Trollip (2001) describe the behavioral, cognitive, and constructivist views of learning and how they can and have been applied in CBT and WBT. I have constructivist leanings so I am interested in learning that involves the learner, where interactivity is a prime characteristic of the learning environment. Many training software packages provide the content, but in a way where the learner is a passive component in the learning (or should I say the teaching).
I have to admit that I am not very familiar with the term “serious games”. In a Google search of other sites I learned that it is using games in non-entertainment sectors. Education is certainly one of those sectors. It sounds like a strategy already being used in education called “edutainment”. Dipak points out that serious games focuses on problem solving and important elements of learning where edutainment focuses on having fun. Serious games is a strategy of using digital game technology to provide the interactivity needed by students as they construct knowledge. Dipak states that edutainment failed because its games were boring and were often nothing more than drills.
Serious games has been slow be accepted as an educational tool due to its high tech needs which had not been available. With the creation of multiplayer games, serious games now has the capability to provide powerful educational tools. More information about serious games can be found at the Serious Games Summit site at http://www.gdconf.com/conference/sgs.htm.
Alessi, S. M., & Trollip, S. R. (2001). Multimedia for learning: Methods and development (3rd ed.). Boston, MA: Allyn and Bacon.
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