English  |  正體中文  |  简体中文  |  Post-Print筆數 : 27 |  Items with full text/Total items : 110180/141115 (78%)
Visitors : 46587338      Online Users : 288
RC Version 6.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version
    Please use this identifier to cite or link to this item: https://nccur.lib.nccu.edu.tw/handle/140.119/67575


    Title: 顧客體驗性價值、自我概念、品牌個性、品牌形象對品牌忠誠度影響之研究-以智慧型手機為例
    A Study of the Impact of Experiential Value, Self-Concept, Brand Identity, Brand Image to Brand Loyalty-Take Smartphone as Example
    Authors: 杜家瑜
    Contributors: 陳建維
    鄭鴻章

    杜家瑜
    Keywords: 品牌個性
    品牌形象
    自我概念
    體驗性價值
    品牌忠誠度
    智慧型手機
    Date: 2013
    Issue Date: 2014-07-21 15:34:58 (UTC+8)
    Abstract: 近年來台灣民眾對於智慧型手機的依賴程度越來越高,隨著通訊費率調降、無線網路發展進步及平價化等因素,智慧型手機已融入民眾生活,不僅是通訊工具,也同時反映著使用者的生活風格與型態,並具有形象傳達的功能.從2008年在Apple宣布以iPhone 3G進軍電信業之後,許多國際品牌大廠開始重視原本只著重在滿足利基型市場的智慧型手機產品;因此,智慧型手機市場 也從2008年開始迅速由以往的利基型市場轉變為高度競爭的「紅海」戰區。當國際手機大廠皆注意到智慧型手機市場且當功能性手機市場幾乎已達到飽和狀態下,智慧型手機的廠商就必須絞盡腦汁來因應即將到來的激烈市場競爭。因此,除了智慧型手機廠商在硬體規格上的不斷推陳出新及價格上的低價競爭,如何去開發品牌以增加顧客忠誠度已是今日各廠商需重視的課題之一。

    本研究以問卷調查的實證研究方式,共得到有效問卷 226份,探討品牌形象、品牌個性、自我概念、顧客體驗性價值會如何影響品牌忠誠度,期望本研究能夠找出提供品牌廠商在品牌事業上的經營或行銷策略建議以期提升消費者的長期品牌忠誠度。

    研究結果發現:自我概念對於品牌個性與品牌形象皆有不同顯著的影響,而顧客體驗性價值受到產品使用行為的影響,顧客體驗價值對於品牌忠誠度也有顯著的影響,品牌個性及品牌形象對於品牌忠誠度皆有正向影響,其中象徵性品牌形象影響最為顯著; 最後,本研究針對不同自我概念下的智慧型手機消費者,根據本研究所論述之品牌個性和品牌形象因素,提出相關行銷建議與策略。
    Reference: 一、 中文部分

    1. IDC市場機構調查之2013亞太區手機市場季度調查報告
    2. 林建煌(2007), 行銷學(初版二刷), 台北:華泰文化出版社。
    3. 李政忠(2003),「從抽樣與統計方法探討網路問卷調查的可行性:比較電話訪談與網路問卷樣本的實質差異性」,廣播與電視,第21期,55-95頁。
    4. 邱志聖(2011),行銷研究-實務與理論應用,第三版,台北:智勝出版社。
    5. 吳芷芸(2003)。兩岸品牌個性之跨文化比較—以報紙廣告為例。未出版之論文。國立政治大學企業管理研究所
    6. 許士軍(1987), 管理學,台北:東華書局。
    7. 楊國樞(1974)。小學與初中學生自我概念的發展及其相關因素。在楊國樞、張春興編著,中國兒童的行為發展(頁 417-463)。臺北市:環宇出版社。
    8. 陳亭羽、施麗琴(2010)。「以直覺模糊評估函數與計分函數界定品牌形象-以手 機為例」。管理科學研究,第六期, 6(2) :1-29。
    9. 鄭英輝 (1998)。品牌人格與產品外顯性對品牌延伸評價的影響。未出版之碩士論文。國立中央大學企業管理研究所

    二、英文部分

    1. Aaker,D. A. (1991). “Guarding the power of a brand name”, New York Times, pp. 313.
    2. Aaker, D. A. (1995). Building strong brands. Brandweek. New York: Oct 2, Vol. 36, Iss. 37; pg. 28-32
    3. Aaker, J. L.(1994). “Dimensions of Brand Personality,” Journal of Marketing Research. (34).
    4. Aaker, J., Benet-martinez, V., & Garolera, J. (2001). “Consumption Symbols as Carriers of Culture:A Study of Japanese and Spanish Brand Personality Constructs,” Journal of Personality and Social Psychology,2001(5):17-21.
    5. Aaker, J., Fournier, S., & Brasel, A. (2004). "When Good Brands Do Bad", Journal of Consumer Research, Vol. 31, No. 1, pp. 1-16.
    6. Anderson, J. C., & Gerbing, W. D. (1988). “Structural Equation Modeling in Practice: A Review and Recommended Two-Step Approach,” Psychological Bulletin, 103 (3), 411-423.
    7. Babin, B.J., Darden, W.R., & Griffin, M. (1994). “Measuring hedonic and utilitarian shopping value,” Journal of Consumer Research, 20(4), 644-656.
    8. Belch, Geroge E., Landon, E., & Laird, Jr. (1977). “Discriminant Validity of a Product-Anchored Self-Concept Measure,” Journal of Marketing Research, May, Vol. 14, p.252-256.
    9. Belk, R. W. (1988). “Possessions and the extended self,”Journal of Consumer Research, 15(2), 139-168.
    10. Belk, R., & Thumbat, G. (2005). “The cult of Macintosh,” Consumption Market and culture, 8, 205-217
    11. Bettman, J.R. (1979). “An Information Processing Theory of Consumer Choice,” Reading, MA: Addison-Wesley.
    12. Biel, A. (1992 ) . “How brand image drives brand equity,” Journal of Advertising Research, Vol.32, No.6, pp.6-12.
    13. Birdwell, Al. E. (1968). “A Study of Influence of Image Congruence on Consumer Choice,” Journal of Business, January, p.76-88
    14. Bhat, S., & Reddy, K. S. (1998). “Symbolic and Functional Positioning of Brands,” Journal of Consumer Marketing, Vol.15, Iss.1, 32-43.
    15. Blackwell, D. R., Miniard, W. P., & Engel, F. J. (2001). Consumer behavior, 9th ed., N.Y.: Harcourt.
    16. Bloch, P.H., & Bruce, G.D. (1984). “The leisure experience and consumer products: An investigation of underlying satisfactions,” Journal of Leisure Research, 16(1), 74-88.
    17. Bolton, R. N., & Katherine N. L. (1999). “A Dynamic Model of Customers’ Usage of Services: Usage as an Antecedent and Consequence of Satisfaction,” Journal of Marketing Research, 36 (May), 171-186.
    18. Burke, B. (1994). “Position, personality, not pricem should frame consumer messages,” Brandweek, 35(36), 20.
    19. Chitturi, R., Raghunathan, R., & Mahajan, V. (2008). “Delight by design: The role of hedonic versus utilitarian benefits,” Journal of Marketing, 72(3), 48-63.
    20. Chaudhuri, A., & Holbrook, B. M. (2002). "Product Class Effects on Brand Commitment and Brand Outcomes: The Role of Brand Trust and Brand Affect," Journal of Brand Management, Vol. 10, No. 1, pp. 33-58.
    21. Chung, K. K., Anne M. L., & Margo, S. (2001). “Consumer Evaluation of Vertical Brand Extensions and Core Brands,” Journal of Business Research, 52, pp. 211-222.
    22. Cyr, D., Head, M., & Ivanov, A. (2006). “Design aesthetics leading to m-loyalty in mobile commerce,” Information & Management, 43(8), 950-963
    23. Cowart, K.O., Fox, G.L., & Wilson, A.E. (2008). “A structural look at consumer innovativeness and self-congruence in new product purchases,” Psychology & Marketing, 25(12), 1111-1130.
    24. Dickson, A., & Sawyer, G. A. (1990). "The Price Knowledge and Search of Supermarket Shoppers," Journal of Marketing, 54 (July), 42-53.
    25. Dobni,D. & Zinkhan,G. M. (1990).“In search of brand Image: A foundation analysis,” Advances in Consumer Research,Vol. 17,No. 1,pp. 110-120.
    26. Dodds, W. B., Monroe, K. B., & Grewal, D. (1991). “Effects of price, brand, and store Information on buyers’ product evaluations,” Journal of Marketing Research, 28(3), 307319.
    27. Dodds, W. B., Monroe, K. B., & Grewal, D. (1991). “Effects of price, brand, and store Information on buyers’ product evaluations,” Journal of Marketing Research, 28(3), 307319.
    28. Dolich, I. J. (1969). “Congruence relationships between self-images and product brands,” Journal of Marketing Research, vol. 6, February, p.80-84
    29. Downing, C. E. (1999). “System Usage Behavior as a Proxy for User Satisfaction: An Empirical Investigation,” Information and Management, 35 (4), 203-216.
    30. Dutton, W., Kovaric, P., & Steinfield, C. (1985). “Computing in the Home: A Research Paradigm,” Computers and the Social Sciences, 1, 5-18.
    31. Engel, J. E., Blackwell, R. D., & Miniard, P. W. (1993). Consumer Behavior, 7th ed., Chicago Dryden Press.
    32. Ericksen, M. K. (1996). “Using self-congruity and ideal-congruity to predict purchase intention: A european perspective,” Journal of Euro-Marketing, 6(1), 41-56.
    33. Fishbein, M., & Ajzen, I. (1975). “Belief, attitude, intention, and behavior: An introduction to theory and research,” Reading, MA: Addison-Wesley.
    34. Fornell,C. (1992).“A national customer satisfaction barometer: The Swedish experience,” Journal of Marketing,Vol. 56,No. 1,pp. 6-22.
    35. Fournier, S. (1998), "Consumers and Their Brands: Developing Relationship Theory in Consumer Research", Journal of Consumer Research, Vol. 24, pp. 343-373.
    36. Gardial, S. F., Clemons, S. D., Woodruff B. R., Schumann, W. D., & Burns, J. M (1994). “Comparing Consumers’ Recall of Prepurchase and Postpurchase Product Evaluation Experiences,” Journal of Consumer Research, 20 (March), 548-560.
    37. Gardner, B. B., & Levy, S. J. (1955). “The product and the brand.,” Harvard Business Review, 33(2), 33-39.
    38. Gatignon, H., & Thomas S. R. (1985). “A Propositional Inventory for New Diffusion Research,” Journal of Consumer Research, 11 (March), 849-867.
    39. Gensch, D.H. (1987), “A Two-Stage Disaggregate Attribute Choice Model.” Marketing Science, 6, pp. 223-39.
    40. Graeff, T. R. (1996). “Image congruence effects on product evaluations: The role of self-monitoring and public/private consumption,” Psychology & Marketing, 13(5), 481-499.
    41. Grewal, D., Monroe, K. B., & Krishnan, R. (1998). “The effects of price-comparison advertising on buyers’ perceptions of acquisition value, transaction value, and behavioral intentions,” Journal of Marketing, 62(2), 4659.
    42. Gronholbt, L., Martensen, A., & Kristensen, K. (2000). “The relationship between Customer Satisfaction and Loyalty: Cross-Industry different,” Total Quality Management, Vol. 11, pp. 509-516.
    43. Grubb, E. L., & Grathwohl, H. L. (1967). “Consumer self-concept, symbolism, and market behavior: A theoretical approach,” Journal of Marketing, 31(4), 22-27.
    44. Hamilton, M., & Sun, X. (2005). “Actual self and ideal brand image: An application of self-congruity to brand image positioning,” International Communication Association. New York, NY, 1-26.
    45. Han, J.K., Chung, S.W., & Sohn, Y.S. (2009). “Technology convergence: When do consumers prefer converged products to dedicated products,” Journal of Marketing, 73(4), 97-108.
    46. Helkkula, A., & Kelleher, C. (2010). “Circularity of customer service experience and customer perceived value,” Journal of Customer Behaviour, 9(1), 37-53.
    47. Hirschman, E.C., & Holbrook, M.B. (1982). “Hedonic consumption: Emerging concepts, methods, and propositions,” Journal of Marketing, 46(3), 92-101.
    48. Holbrook, M.B. (1994). “The nature of customer value: An axiology of services in the consumption experience,”In R.T. Rust & R.L. Oliver (Eds.), Service Quality: New Directions in Theory and Practice (pp. 21-71). Newbury Park, CA: Sage Publications.
    49. Hogg, M. K., Cox, A. J., & Keeling, K. (2000). “The impact of self-monitoring on image congruence and product/brand evaluation,” European Journal of Marketing, 34(5/6), 641-667.
    50. Howard, J. A., & J. N. Sheth (1969). “The Theory of Buyer Behavior,” 1st Edition, New York: Wiley.
    51. Jamal, A., & Goode, M. H. (2001). “Consumers and brands: A study of the impact of self-image congruence on brand preference and satisfaction,” Marketing Intelligence and Planning, 19(7), 482-492.
    52. James, W. (1890). “The principles of psychology,” New York: Holt.
    53. Johar, J. S., & Sirgy, M. J. (1991). “Value-expressive versus utilitarian advertising appeals: When and why to use which appeal,” Journal of Advertising, 20(3), 23-33.
    54. Jones, T. O., & Sasser, W. E. (1995). “Why satisfied customers defect,” Harvard Business Review, Vol. 73,No. 1,pp. 88-99.
    55. Kaplan, M.D. (2009). “The relationship between perceived innovativeness and emotional product responses: A brand oriented approach,” Innovative Marketing, 5(1), 39-47.
    56. Kayes, J. B. (1999). “Antecedents and consequences of brand personality,” [Electronic version]. Unpublished doctoral dissertation, Mississippi State University.
    57. Kekre, S., Krishnan, S. M., & Srinivasan, K. (1995). “Drivers of Customer Satisfaction for Software Products: Implications for Design and Service Support,” Management Science, 41 (9), 1456-1470.
    58. Keller, K. L. (1993). “Conceptualizing, Measuring, and Managing Customer-Based Brand Equity,” Journal of Marketing, Jan, Vol. 57, Iss. 1, p. 1-22
    59. Keller, K. L. (1998). “Strategic brand management: Building, measuring, and managing brand equity (1st ed.),” Upper Saddle River, NJ: Prentice Hall.
    60. Keller, K. L. (2001). “Building customer-based brand equity,” Marketing. Management, Chicago: Jul/Aug.Vol. 10, Iss. 2; pg. 14-19
    61. Kamins, M. A., Marks, L. J., & Skinner, D. (1991). “Television commercial evaluation in the context of program-induced mood: Congruency versus consistency effects,” Journal of Advertising, 20 (2), 1-14.
    62. Kirmani, A., & Zeithaml, V.A. (1993), “Brand Equity & Advertising: Advertising`s Role in Building Strong Brands,” Lawrence Erlbaum Associates, Hilldale, NJ, pp. 143-62.
    63. Kleine, R. E., Kleine, S. S., & Kernan, J. B. (1993). “Mundane consumption and the self: A social-identity perspective,” Journal of Consumer Psychology, 2(3), 209-235.
    64. Kressmann, F., Sirgy, M. J., Herrmann, A., Huber, F., Huber, S., & Lee, Dong-Jin. (2006). “Direct and indirect effects of self-image congruence on brand loyalty,” Journal of Business Research, 59(9), 955-964.
    65. Kulviwat, S., Bruner, G.C., & Al-Shuridah, O. (2009). “The role of social influence on adoption of high tech innovations: The moderating effect of public/private consumption,” Journal of Business Research, 62(7), 706-712.
    66. Lee, H. J., Lim, H., Jolly, L.D., & Lee, J. (2009). “Consumer lifestyles and adoption of high- technology products: A case of South Korea,” Journal of International Consumer Marketing, 21(2), 153-167.
    67. Lim, H., Widdows, R., & Park, J. (2006). “M-loyalty: Winning strategies for mobile carriers,” Journal of Consumer Marketing, 23(4), 208-218.
    68. Levy, S. J. (1959). “Symbols for sale,” Harvard Business Review, 37(4), 117-124.
    69. Loudon, D., & Bitta, A. (1993). Consumer behavior. New York: McGraw-Hill.
    70. Mathwick, C., Malhotra, N., & Rigdon, E. (2001). “Experiential Value: Conceptualization, Measurement and Application in the Catalog and Internet Shopping Environment,” Journal of Retailing, 77(1), 39-56.
    71. McCarthy, J., & Wright, P. (2004). Technology as Experience. Cambridge, Massachusetts: The MIT Press.
    72. Malhotra, N. K. (1981). “A Scale to Measure Self-Concepts, Person Concepts, and Product Concepts,” Journal of Marketing, Nov, Vol. 18, p. 456-464.
    73. Malhotra, N. K. (1988). “Self-concept and product choice: An integrated perspective,” Journal of Economic Psychology, 9(1), 1-28.
    74. Mangleburg, T., Sirgy, M. J., Grewal, D., Axsom, D., Hatzios, M., & Claiborne, C. B. (1998). “The moderating effect of prior experience in consumers` use of user-image based versus utilitarian cues in brand attitude,” Journal of Business Psychology, 13 (1), 101-113.
    75. Marquardt, A. (2005). “Self and brand image congruence: Driving consumer value,” American Marketing Association. Conference. Proceedings, Chicago, 16, 286-287.
    76. McAlister, L., & Pessemier, E. (1982). “Variety Seeking Behavior: An Interdisciplinary Review,” Journal of Consumer Research, 9, 311-322.
    77. Park, C. W., Jaworski, B. J., & MachInnis, D. J. (1986). “Strategic Brand Concept-Image Management,” Journal of Marketing, Vol. 50, Iss.4, p.135-145.
    78. Parker, B. T. (2005). “This brand`s for me: Brand personality and user imagery based self-congruity,” Unpublished doctoral dissertation, University of Florida, Florida.
    79. Park, H., Lim, H.; Kim, Y. K. (2013). “Experiential value: Application to innovative consumer technology products,” Journal of Customer Behavior, Vol. 12, No. 1, pp. 7-24
    80. Phau, I., & Lau, K. C. (2001). “Brand personality and consumer self-expression: Single or dual carriageway,” Journal of Brand Management, 8(6), 428-444.
    81. Plummer, J. T. (1984). “How personality makes a difference,” Journal of Advertising Research, 24(6), 27-31.
    82. Rossiter, J.R., & Percy, L. (1987). “Advertising and promotion management,” McGraw-Hill, New York, N.Y.*
    83. Son K. L., Ahearne, M., Schillewaert, N. (2010). “Resistance to Brand Switching When a Radically New Brand Is Introduced: A Social Identity Theory Perspective,” Journal of Marketing, Vol. 74, No. 6, pp. 128-146.
    84. Scherf, K. (2006). “Trends in consumer technology: Defining and sizing the market,” A Parks Associates white paper. Dallas, TX: Parks Associates.
    85. Schiffman, L. G., & Kanuk, L. L. (2000). Consumer Behavior 7th, N.J.: Prentice Hall.
    86. Shih, C. F., & Venkatesh, A. (2004). “Beyond Adoption: Development and Application of a Use-Diffusion Model,” Journal of Marketing, 68 (January), 59-72.
    87. Silvester, S. (2010). “Mobile Mania: A Manual for the Second Internet Revolution,” London: Young & Rubicam EMEA.
    88. Sirgy, M. J. (1982). “Self-Concept in Consumer Behavior: A Critical Review,” Journal of consumer Research, Dec., Vol. 9, Iss. 3, p.287-300
    89. Sirgy, M. J., Johar, J. S., & Wood, M. (1986). “Determinants of product value expressiveness: Another look at conspicuousness, differentiation, and common usage,” In N. Malhotra (Ed.), Developments in Marketing Science (vol. 9, pp. 35-39). Atlanta, GA: Academy of Marketing Science.
    90. Sirgy, M. J., Johar, J. S., Samli, A. C., & Claiborne, C. B. (1991). “Self-congruity versus functional congruity: Predictors of consumer behavior,” Journal of Academic Marketing Science, 19 (4), 363-375.
    91. Sirgy, M. J., Grzeskowiak, S., & Su, C. (2005). “Explaining housing preference and choice: The role of self-congruity and functional congruity,” Journal of Housing and the Built Environment, 20(4), 329-347.
    92. Solomon, M. R. (1983). “The Role of Products as Social Stimuli: A Symbolic Interactionism Perspective,” Journal of Consumer Research, 10, 319-329.
    93. Solomon, M. R. (2004). “Consumer Behavior: Buying, having, and being (6th ed.),” Upper Saddle River, NJ: Pearson Prentice Hall.
    94. Sommers, S. M. (1964). “Product Symbolism and the Perception of Social Strata,” Proceedings of the American Marketing Association, Vol.22, p.200-216.
    95. Srivastava, K. R., Shocker, D.A., & George S. D. (1978). “An Exploratory Study of the Influences of Usage Situation on Perceptions of Product Markets,” Advances in Consumer Research, Vol. 5, Keith Hunt, ed., Chicago: Association for Consumer Research, 32-37.
    96. Ram, S., & Jung, H. S. (1990). “The Conceptualization and Measurement of Product Usage,” Journal of the Academy of Marketing Science, 18 (1), 67-76.
    97. Ram, S., & Jung, H. S. (1994), “Innovativeness in Product Usage: A Comparison of Early Adopters and Early Majority,” Psychology & Marketing, 11 (1), 57-67.
    98. Wilkie, W. L. (1994). Consumer Behavior. 3rd ed., N.J.: John Wiley and Sons.
    99. Woodruff, B. R. (1997). “Customer Value: The Next Source for Competitive Advantage,” Journal of the Academy of Marketing Science, 25 (Spring), 139-153.
    100. Zaichkowsky, J. L. (1985). “Familiarity: Product Use, Involvement or Expertise?” Advances in Consumer Research, Elizabeth C. Hirschman and Morries B. Holbrook, eds. Provo, UT: Association for Consumer Research, 12, 296-299.
    101. Zeithaml, V. A. (1988). “Consumer perceptions of price, quality, and value: A means-end model and synthesis of evidence,” Journal of Marketing, 52(July), 222.
    三、網頁資料

    1. 2012台灣智慧型手機使用行為大調查 (民 102年 1月25日)。Inside 硬塞的網路趨勢觀察:(民 103年 3月2日)
    取自: http://www.inside.com.tw/2013/01/25/2012-taiwan-smartphone-survey

    2. 黃姵珊(民 102年 8月13日)。Google調查:台灣智慧手機普及率51% 依賴度81%居冠亞洲。鉅亨網 (民 103年 3月2日)
    取自: http://news.cnyes.com/Content/20130813/kh9nwe1yi2n3k.shtml

    3. Christopher Null (2012, Dec 19). 2012 Reader Satisfaction Survey: 45,000 PCWorld readers name the brands they love. PCWorld.com website (2014, Jan 22)
    Retrieved from: http://www.pcworld.com/article/2020723/45-000-pcworld-readers-name-the-brands-they-love-and-love-to-hate.html
    Description: 碩士
    國立政治大學
    國際經營與貿易研究所
    102351002
    102
    Source URI: http://thesis.lib.nccu.edu.tw/record/#G0102351002
    Data Type: thesis
    Appears in Collections:[國際經營與貿易學系 ] 學位論文

    Files in This Item:

    File SizeFormat
    100201.pdf1687KbAdobe PDF2405View/Open


    All items in 政大典藏 are protected by copyright, with all rights reserved.


    社群 sharing

    著作權政策宣告 Copyright Announcement
    1.本網站之數位內容為國立政治大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用,惟仍請適度,合理使用本網站之內容,以尊重著作權人之權益。商業上之利用,則請先取得著作權人之授權。
    The digital content of this website is part of National Chengchi University Institutional Repository. It provides free access to academic research and public education for non-commercial use. Please utilize it in a proper and reasonable manner and respect the rights of copyright owners. For commercial use, please obtain authorization from the copyright owner in advance.

    2.本網站之製作,已盡力防止侵害著作權人之權益,如仍發現本網站之數位內容有侵害著作權人權益情事者,請權利人通知本網站維護人員(nccur@nccu.edu.tw),維護人員將立即採取移除該數位著作等補救措施。
    NCCU Institutional Repository is made to protect the interests of copyright owners. If you believe that any material on the website infringes copyright, please contact our staff(nccur@nccu.edu.tw). We will remove the work from the repository and investigate your claim.
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback