本研究的目的在探討不同的問題解決策略(一般問題解決、引導問題解決)、數位學習環境(數位遊戲學習、對話情境學習)及問題解決信心(高信心組、低信心組)對國中二年級學生在能源知識概念的學習成效(知識理解、知識應用)與學習態度之影響。研究對象為國中二年級學生，研究樣本為北部某國中，隨機抽取八個班級實驗共264位學習者。所有學生均受過電腦操作技能、網頁瀏覽、文書處理等相關基本能力之課程。
研究發現：(1)高信心組在能源種類與應用在知識應用面向的學習成效上，表現高於低信心組。(2)對話情境學習組在能源教學活動的學習動機面向上，表現高於數位遊戲學習組；(3)引導性問題解決策略在能源教學活動的學習動機面向上，表現高於使用一般性問題解決策略；(4)引導性問題解決策略在學習連結與學習意願面向上，表現高於使用一般性問題解決策略；(5)高問題解決信心在整體學習態度的表現上高於低問題解決信心。

The main purpose of this study was to examine the effects of different problem-solving strategies (problem-solving vs. guided problem-solving), digital learning environment (game-based learning vs. situational dialogue), and different levels of problem-solving confidence (high vs. low) on eighth-graders’ learning of energy concepts. The subjects were junior high school students and participants were 264 eighth graders from the north part of Taiwan. All students were acquired with the basic computer skills including web browsing, word processing, and other related basic skills.
The results revealed that: (a) the higher problem-solving confidence group achieved better performance on knowledge application than the low confidence group; (b) the situational dialogue group possessed higher degree of learning motivation than the game-based learning group, (c) the guided problem-solving group showed stronger learning motivation and willingness than the problem-solving group; and (d) the high problem-solving confidence group revealed higher overall learning attitudes than the low problem-solving confidence group.

王晃三、顧志遠(2001)。問題解決學。台北：東華書局。
田振榮、林建成(1995)。能源教育的新方向-STS模式的探討，能源技刊，25卷，3期，頁99-107。
李佳蓉(1996)。電腦益智遊戲對國小高年級學童的推理能力、問題解決能力及電腦態度之影響。國立台南大學國民教育研究所碩士論文，台南市。
李佩娟(2006)。大六技巧網路輔助教學環境對提昇大學生資訊問題解決能力、批判思考意向與能力之研究。國立臺南大學科技發展與傳播研究所碩士論文，台南市。
李登隆、李美芬(2004)。資訊融入專題導向學習對國小學生自然科學習態度與問題解決能力之影響。科學教育研究與發展季刊，2004專刊，69-94。
吳世彬(1993)。新文化事業電腦多媒體。自動化科技，111，62-65。
林怡珊(2008)。自然科問題本位學習對六年級學生科學概念與科學學習動機之影響。中原大學教育研究所碩士論文，桃園縣。
周昇馨、孫培真(2008)。遊戲式學習之探討:模式、設計與應用，第四屆臺灣數位學習發展研討會。
施淑嫺(2010)。國小三年級學生社會學習領域問題解決教學法之行動研究。國立臺東大學進修部暑期社教碩士班學位論文，台東縣。
陳建州、林彥珉(2008)。能源政策與能源教育的緣起。嶺東通識教育研究學刊， 2卷，3期，1-12。
陳韋銘(2007)。數位遊戲系統的問題解決能力探究－以建設波谷蘇島為例。
陳映如(2012)。從日本福島核災探討氣候變遷風險與核能風險認知之研究。未出版碩士論文。國立中央大學產業經濟研究所，桃園縣。
游朝煌(1994)。多媒體在電腦輔助教學之應用現況與發展趨勢。資訊與教育，44，42-44。
程金保、商育滿、胡開惠(2007)。能源教育大不同－以歐美為例探討國內外推行能源教育之差異。經濟部能源局能源報導，民 97 年 5 月。32。
黃茂在、陳文典(2004)。“問題解決” 的能力。科學教育，273，21-41。
黃春金(2003)。探索教育活動對國小高年級學童的問題解決能力與態度之影響研究。國立屏東教育大學教育學系碩士論文，屏東縣。
黃麗分、吳庭瑜、侯世環、洪瑞雲(2012)。回饋類型、問題呈現方式與練習對問題解決的影響。教育心理學報，43卷，4期，頁129-148。
黃佩純(2009)。融合科技接受模型與動機理論探討數位遊戲式學習之學習態度與學習滿意度-以商業類科高職生為例。國立高雄師範大學資訊教育研究所碩士論文，高雄市。
張春興(2001)。教育心理學。台北市：東華書局。
張弘典(2008)。能源小蜜蜂以數位遊戲式學習輔助能源教育。國立中央大學網路學習科技研究所碩士論文，桃園縣。
張文芬(2005)。國小高年級學童之學習風格與科學問題解決能力之研究。國立屏東教育大學數理教育研究所碩士論文，屏東縣。
曾秋森(1995)。問題解決教學法在科技教育的角色與功能之探討。中學工藝教育，28卷，8期，頁17-22。
鄒景平(2003)。《數位學習的最佳導引》第一章。頁1-19。
經濟部能源局(2010)，能源產業技術白皮書。
溫在正(2001)。問題解決歷程之架構分析研究。中原大學工業工程系所碩士論文。桃園縣。
趙美聲、黃仁竑(2003)。數位學習系統中學習支援工具之探究。隔空教育論叢，15，1-12。
劉湘川、許天維、林原宏(1993)。問題解決的研究與教學。國教輔導，33卷，2期，頁13-18。
鄭昭明(1993)。認知心理學：理論與實踐，台北市：桂冠出版社。
廖家瑜、連啟瑞、盧玉玲(2013)。國小學童月亮數位遊戲學習之發展與學習成效之評估。科學教育學刊，21卷，3期，頁317-344。
羅素貞(1996)。問題表徵與問題解決。屏東師院學報，9，149-176。
Ausubel, D. P. (1966). The effects of cultural deprivation on learning patterns. In Staten W. Webster (Ed.), Understanding the educational problems of the disadvantaged learner. San Francisco.
Andone, D., Dron, J., Pemberton, L., & Boyne, C. (2007). E-learning environments for digitally-minded students. Journal of Interactive Learning Research, 18(1), 41-53.
Annetta, L. A. (2008). Video games in education: Why they should be used and how they are being used. Theory Into Practice, 47(3), 229-239.
Antvorskov, S., & Rasmussen, H. F. (2009). The Contract: An educational computer game analysing and optimising renewable energy and energy efficiency in schools. In Proceedings of ISES World Congress 2007 (Vol. I–Vol. V) (pp. 3035-3039). Springer Berlin Heidelberg.
Ausubel, D.P. (1968). Educational psychology: A cognitive view. New York: Holt, Rinehart & Winston.
Barab, S., Scott, B., Siyahhan, S., Goldstone, R., Ingram-Goble, A., Zuiker, S., et al. (2009). Transformational play as a curricular scaffold: using videogames to support science education. Journal of Science Education & Technology, 18(4), 305–320.
Bang, M., Gustafsson, A., & Katzeff, C. (2007). Promoting new patterns in household energy consumption with pervasive learning games. In Persuasive Technology (pp. 55-63). Springer Berlin Heidelberg.
Bowman, R.F. (1982). A Pac-Man theory of motivation. Tactical implications for classroom instruction. Educational Technology, 22(9), 14-17.
Brom, C., Preuss, M., & Klement, D. (2011). Are educational computer micro-games engaging and effective for knowledge acquisition at high-schools? A quasi-experimental study. Computers & Education, 57(3), 1971–1988.
Bruner, J. (1990). Acts of meaning. Cambridge: Harvard University Press
Charsky, D. (2010). From edutainment to serious games: A change in the use of game characteristics. Games and Culture, 5(2), 177-198.
Chumley-Jones, H. S., Dobbie, A., & Alford, C. L. (2002). Web-based learning: sound educational method or hype? A review of the evaluation literature. Academic Medicine, 77(10), 86-93
Clark, D., Nelson, B., Sengupta, P., & D’Angelo, C. (2009). Rethinking science learning through digital games and simulations: Genres, examples, and evidence. Presented at the Learning science: Computer games, simulations, and education workshop sponsored by the National Academy of Sciences, Washington, D.C.
Collins, A. (2006). Cognitive apprenticeship. In R. K. Sawyer (Ed.), The Cambridge handbook of the learning sciences (pp. 47-60). New York: Cambridge University Press.
Darabi, A., Nelson, D. W., Meeker, R., Liang, X., & Boulware, W. (2010). Effect of worked examples on mental model progression in a computer-based simulation learning environment. Journal of Computing in Higher Education. 22(2), 135-147.
Davey, G. C., Jubb, M., & Cameron, C. (1996). Catastrophic worrying as a function of changes in problem-solving confidence. Cognitive Therapy and Research, 20(4), 333-344.
Denis, G., & Jouvelot, P. (2005). Motivation-driven educational game design: applying best practices to music education. Paper presented at the 2005 ACM SIGCHI International Conference on Advances in Computer Entertainment Technology, Valencia, Spain.
Dewey, J. (1910). How we think. Boston: Heath.
DeWaters, J.E., Powers, S.E., & Graham, M. (2007). Developing an energy literacy scale. In Proceedings of the ASEE annual conference and exposition, Honolulu, HI.
DeWaters, J. E., & Powers, S. E. (2011). Energy literacy of secondary students in New York State (USA): A measure of knowledge, affect, and behavior. Energy Policy, 39(3), 1699-1710.
Diakidoy, I. A. N., Kendeou, P., & Ioannides, C. (2003). Reading about energy: The effects of text structure in science learning and conceptual change. Contemporary Educational Psychology, 28(3), 335-356.
Dickey, M. D. (2005). Three-dimensional virtual worlds and distance learning: Two case studies of active worlds as a medium for distance education. British Journal of Educational Technology, 36(3), 439–451.
Dickey, M. D. (2006). “Ninja Looting” for instructional design: The design challenges of creating a game-based learning environment. Paper presented at the ACM SIGGRAPH 2006 conference, Boston.
Dondlinger, M. J. (2007). Educational video game design: A review of the literature. Journal of Applied Educational Technology, 4(1). 21-31.
Doménech, J. L., Gil-Pérez, D., Gras-Martí, A., Guisasola, J., Martínez-Torregrosa, J., Salinas, J., Trumper, R., Valdés, P., & Vilches, A. (2007). Teaching of energy issues: A debate proposal for a global reorientation. Science & Education, 16(1), 43-64.
Drigas, A. S., Vrettaros, J., Koukianakis, L. G., & Glentzes, J. G. (2006). A virtual lab and e-learning system for renewable energy sources. architecture, 6(11), 12-16.
Duit, R. (1984). Learning to the energy concept in school-empirical results from the philippines and west germany. Physics Education, 19(2), 59-66.
D'Zurilla, T. J., & Goldfried, M. R. (1971). Problem solving and behavior modification. Journal of abnormal psychology, 78(1), 107-126.
El Mawas, N., & Cahier, J. P. (2012). Towards participative and knowledge-intensive serious games. In Serious Games Development and Applications (pp. 86-97). Springer Berlin Heidelberg.
Felder, R.M., & Silverman, L.K. (1988). Learning and teaching styles in engineering education, Engineering Education, 78(7), 674–681.
Gagne, R. M. (1977). The conditions of learning. Third Edition. New York: Holt, Rinehart and Winston, Inc.
Gagne, E. D., Yekovich, C. W., & Yekovich, E R. (1993). The cognitive psychology of school learning. New York: Harper-Collins.
Ge, X., & Land, S. M. (2003). Scaffolding students’ problem-solving processes in an ill-structured task using question prompts and peer interactions. Educational Technology Research and Development, 51(1), 21-38.
Gee, J.P. (2004). Learning by design: Good video games as learning machines. In Proceedings of the Game Developers’ Conference, [online], http://www.academiccolab.org/resources/documents/Game%20Paper.pdf [accessed 11th May 2007]
Gee, J. P. (2008). Learning and games. The ecology of games: Connecting youth, games, and learning, 3, 21-40.
Glass, A., & Holyoak, K. (1986). Cognition. New York: Random House
Gros, B. (2007). Digital games in education: Design of game-based learning environments. Journal of Research on Technology in Education, 40(1), 23-38.
Gudmundsdottir, S. (1995). The narrative nature of pedagogical content knowledge. In H. McEwan & K. Egan (Eds.), Narrative in teaching, learning, and research. NY: Teachers College Press.
Halverson, R., Shaffer, D., Squire, K., & Steinkuehlr, C. (2006). Theorizing games in education. Paper presented at the 7th international conference on Learning Sciences, Bloomington, IN.
Harmon, S. W., & Jones, M. G. (2001). An analysis of situated web-based instruction, Educational Media International. 38(4), 271-280.
Hatch, L. (1988). Problem solving approach. In W. H. Kemp & A. E. Schwaller (Eds.), Instructional strategies for technology education (pp. 87-98). 37th Yearbook of the Council on Technology Teacher Education. Mission Hills, CA: Glencoe.
Henry, J. B. (1990). Computers in medical education: information and knowledge management, understanding, and learning. Human pathology, 21(10), 998-1002.
Heppner, P. P., & Anderson, W. P. (1985). The relationship between problem-solving self-appraisal and psychological adjustment. Cognitive therapy and research, 9(4), 415-427.
Heppner, P., & Baker, C. E. (1997). Applications of the problem solving inventory. Measurement & Evaluation in Counseling & Development (American Counseling Association), 29(4), 229-243.
Herrington, J., Oliver, R., Herrington, T., & Sparrow, H. (2000). Towards a new transition of online instruction: Using situated learning theory to design web-based units. Paper presented at the ASCILITE 2000 Conference, December 9-14, 2000, Coffs Harbour, Australia
Hui, S., & Cheung, K. P. (1999). Developing a web-based learning environment for building energy efficiency and solar design in Hong Kong. Solar Energy, 67(1), 151-159.
Hodson, D. (2003). Time for action: Science education for an alternative future, International Journal of Science Education, 25(6), 645-670.
Hope, G. (2002). Solving problems: Young children exploring the rules of the game, Curriculum Journal, 13(3), 265-278.
Huang, W. H., Huang, W. Y., & Tschopp, J. (2010). Sustaining iterative game playing processes in DGBL: The relationship between motivational processing and outcome processing. Computers & Education, 55(2), 789–797.
Huberman, M. (1995). Working with life-history narratives. In H. McEwan & K. Egan (Eds.), Narrative in teaching, learning, and research. NY:Teachers College Press.
Jennings, M. (2001). Best practices in corporate training and the role of aesthetics: Interviews with eight experts. Paper presented at the 2001 ACM SIGCPR conference on Computer Personnel Research, San Diego, California. Available http://portal.acm.org/citation.cfm?id=371209.371239
Jonassen, D. H. (1997). Instructional design models for well-structured and ill-structured problem-solving learning outcomes. Educational Technology Research and Development, 45(1), 65-94.
Johnson, R. E., Chang, C. H., & Lord, R. G. (2006). Moving from cognition to behavior: What the research says. Psychological Bulletin, 132(3), 381-415.
Jonassen, D. H., & Hernandez-Serrano, J. (2002). Case-based reasoning and instructional design: Using stories to support problem solving. Educational Technology Research and Development, 50(2), 65-77.
Kardash, C. M., & Howell, K. L. (2000). Effects of epistemological beliefs and topic-special beliefs on undergraduates’ cognitive and strategic processing of dual-positional text. Journal of Educational Psychology, 92(3), 524-535.
Kay, R. H., & Knaack, L. (2009). Assessing learning, quality and engagement in learning objects: The learning object evaluation scale for students (LOES-S). Educational Technology Research and Development, 57(2), 147-168.
Khan, B. H. (2001). Web-based training: An introduction. In B. H. Khan (Ed.), Web-based training. (pp. 5-12). Englewood Cliffs, NJ: Educational Technology Publications.
Kiili, K. (2005). Digital game-based learning: Towards an experiential gaming model. The Internet and higher education, 8(1), 13-24.
Kim, B., Park, H., & Baek, Y. (2009). Not just fun, but serious strategies: Using meta-cognitive strategies in game-based learning. Computers & Education, 52(4), 800–810.
Kirriemuir, J. (2002). Video gaming, education and digital learning technologies. D-Lib Magazine, 8(2).
Kirriemuir, J., & McFarlane, A. (2004). Report 8: Literature review in games and learning. Futurelab Series. Retrieved April 22, 2009, from http://www.futurelab.org.uk/resources/documents/lit_reviews/Games_Review.pdf
Klawe, M. (1999). Computer games, education and interfaces: The E-GEMS project. In Proceedings of the graphics interface conference (pp. 36–39).
Klausmeier, H. J. (1985). Educational psychology, 5th edition. New York: Harper and Row.
Klopfer, E., & Yoon, S. (2005). Developing games and simulations for today and tomorrow’s tech savvy youth. Tech Trends, 49(3), 33-41.
Knight, J. K., & Wood, W. B. (2005). Teaching more by lecturing less. Cell Biology Education, 4(4), 298-310.
Krulik, S., & Rudnick, J. A. (1980). Problem solving, Allyn and Bacon, Boston.
Kurnaz, M. A. (2007). Üniversite 1. sınıf seviyesinde enerji kavramının öğrenim durumlarının analizi. Unpublished Master Thesis, University of Karadeniz Technical, Trabzon, Türkiye.
Kurnaz, M. A. & Çalık, M. (2009). A thematic review of ‘energy’ teaching studies: Focuses, needs, methods, general knowledge claims and implications. Energy Education Science and Technology Part B: Social and Educational Studies, 1(1), 1-26.
Kyprianou, K., Loizidou, P., Charalambous, P., Matsikaris, G., & Yiannakis, I. (1997). First steps in science: Sixth-grade science teachers manual. Nicosia, CY: Government of Cyprus.
Lave, J., & Wenger, E. (1991). Situated learning: Legitimate peripheral participation. Cambridge university press.
Lee, C. Y., & Chen, M. P. (2009). A computer game as a context for non-routine mathematical problem solving: The effects of type of question prompt and level of prior knowledge. Computers & Education, 52(3), 530-542.
Lovett, M. C. (2002). Problem solving. In H. Pashler & D. Medin (Eds.), Stevens’ Handbook of experimental psychology: Vol. 2. Memory and cognitive processes (pp. 317-362). New York: Wiley.
Lucangeli, D., Tressoldi, P. E., & Cendron, M. (1998). Cognitive and metacognitive abilities involved in the solution of mathematical word problems: Validation of a comprehensive model. Contemporary Educational Psychology, 23(3), 257-275.
McCloskey, M. (1983). Intuitive Physics. Scientific American, 248(4), 122-130.
Nicholls, G. & Ogborn, J. (1993). Dimensions of Children’s Conceptions of Energy. International Journal of Science Education, 15(1), 73-81.
Millar, R. (2000). Energy. In D. Sang (Ed.), Teaching secondary physics (pp. 1 – 43). London: John Murray.
Mikropolous, T. A. & Natsis, A. (2011). Educational virtual environments: A ten-year review of empirical research (1999-2009). Computers & Education, 56(3), 769-780.
Monroy, C., Klisch, Y., & Miller, L. M. (2011). Emerging contexts for science education: embedding a forensic science game in a virtual world. InProceedings of the 2011 iConference (pp. 622-629). ACM.
Pajares, F., & Kranzler, J. (1995). Self-efficacy beliefs and general mental ability in mathematical problem-solving. Contemporary Educational Psychology, 20(4), 426-443.
Paraskeva, F., Mysirlaki, S., & Papagianni, A. (2010). Multiplayer online games as educational tools: Facing new challenges in learning. Computers & Education, 54(2), 498-505.
Papadouris, N., Constantinou, C. P., & Kyratsi, T. (2008). Students' use of the energy model to account for changes in physical systems. Journal of Research in science teaching, 45(4), 444-469.
Pearson, G. & Young, A. T. (2002). Technically speaking: Why all Americans need to know more about technology. National Academy Press: Washington, DC.
Pedaste, M. & Sarapuu, T. (2006). The factors influencing the outcome of solving story problems in a web-based learning environment. Interactive Learning Environments, 14(2), 153-176.
Pines, A. L., & West, L. H. (1986). Conceptual understanding and science learning: An interpretation of research within a sources‐of‐knowledge framework. Science Education, 70(5), 583-604.
Polya, G. (1957). How to solve it: A new method of mathematical method.Solved Gifted Child Today. March/April, 61-63.
Posner, G. J., Strike, K. A., Hewson, P. W., & Gertzog, W. A. (1982). Accommodation of a scientific conception: Toward a theory of conceptual change. Science Education, 66(2), 211-227.
Prensky, M. (2001). Digital Natives, Digital Immigrants. On the Horizon, 9(5).
Prensky, M. (2003). Digital game-based learning. ACM Computers in Entertainment, 1(1), 1-4.
Prensky, M. (2007). Digital game-based learning. Saint Paul, MN: Paragon House.
Rendl, N. K. (2000). The Infusion and Evaluation of KEEP (K-12 Energy Education Program) as a Middle School Science Curriculum Resource inn Seventh Grade at John Muir Middle School (Unpublished Masters Thesis). University of Wisconsin, Stevens Point, WI.
Rifner, P. J., & Feldhusen, J. F. (1997). Caputuring gifted students’ logical thinking using chess. Gifted Child Today Magazine. 1(20), 36-39.
Schön, D. (1983). The Reflective Practitioner: How Professionals Think in Action, New York: Basic Books.
Shaffer, D. W., Squire, K. D., Halverson, R. & Gee, J. P. (2005). Video games and the future of learning. Phi Delta Kappan, 87(2), 104–111.
Squire, K. (2005). Game-based learning: Present and future state of the field. Madison, WI: University of Wisconsin-Madison Press.
Squire, K., Giovanetto, L., Devane, B., & Durga, S. (2005). From users to designers: Building a self-organizing game-based learning environment. Tech Trends, 49(5), 34–42, 74.
Sternberg, R. J. (1977). Intelligence, information processing, and analogical reasoning: The componential analysis of human abilities. Lawrence Erlbaum.
Suryanarayana, L., & Hjelm, J. (2002). Profiles for the situated web. In Proceedings of the 11th international conference on World Wide Web (pp. 200-209). ACM.
Tan, J., & Biswas, G. (2007). Simulation-based game learning environments: Building and sustaining a fish tank. In Digital Game and Intelligent Toy Enhanced Learning, 2007. DIGITEL'07. The First IEEE International Workshop on (pp. 73-80). IEEE.
Torrente, J., Moreno-Ger, P., Martínez-Ortiz, I., & Fernandez-Manjon, B. (2009). Integration and deployment of educational games in e-learning environments: The learning object model meets educational gaming. Educational Technology & Society, 12(4), 359–371.
Totten M. & Anderson D. (1997) CD-ROM and Internet: Critical tools for renewable energy professionals. Renewable Energy, 10(2-3), 457-469.
Trumper, R. (1997). Applying conceptual conflict strategies in the learning of the energy concept. Research in Science & Technological Education, 15(1), 5-18.
van Eck, R. (2007). Six ideas in search of a discipline. In B.E. Shelton & D.A. Wiley (Eds.), The design and use of simulation computer games in education (pp. 31-60). Rotterdam: Sense Publishing.
Wang, L. C., & Chen, M. P. (2010). The effects of game strategy and preference-matching on flow experience and programming performance in game-based learning. Innovations in Education and Teaching International, 47(1), 39–52.
Waraich, A. (2004). Using narrative as a motivating device to teach binary arithmetic and logic gates. Paper presented at the 9th annual SIGCSE Conference on Innovation and Technology in Computer Science Education, Leeds, United Kingdom.
Warren, S. J., Dondlinger, M. J., & Barab, S. A. (2008). A MUVE Towards PBL Writing: Effects of a digital learning environment designed to improve elementary student writing. Journal of Research on Technology in Education, 41(1). 113-140.
Watts, D.M. (1983). Some alternative views of energy. Physics Education, 18(5), 213-217.
Wei, T., Li, Y. (2010). Design of educational game: a literature review. Transactions on edutainment IV, Zhigeng Pan, Adrian David Cheok, Wolfgang Möller, Xiaopeng Zhang, and Kevin Wong (Eds.). Lecture Notes In Computer Science, Vol. 6250. Springer-Verlag, Berlin, Heidelberg 266-276.
White, R. T., & Gunstone, R. F. (1989). Metalearning and conceptual change. International Journal of Science Education, 11(5), 577-586.
Wlodkowski, R.J. (2008). Enhancing adult motivation to learn: A comprehensive guide for teaching all adults. San Francisco: Jossey-Bass.
Wouters, P., van der Spek, E., & Van Oostendorp, H. (2009). Current practices in serious game research: A review from a learning outcomes perspective. Games-based learning advancements for multi-sensory human computer interfaces: techniques and effective practices, 232-250.
Zagal, J. P., Nussbaum, M., & Rosas, R. (2000). A model to support the design of multiplayer games. Presence, 9(5), 448-462.