Documents disponibles écrits par cet auteur

Approaches to rut depth prediction in semirigid asphalt pavements / Jun Yang in Journal of engineering mechanics, Vol. 135 N° 6 (Juin 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 510-516 Titre : Approaches to rut depth prediction in semirigid asphalt pavements Type de document : texte imprimé Auteurs : Jun Yang, Auteur ; Haizhu Lu, Auteur ; Haoran Zhu, Auteur Article en page(s) : pp. 510-516 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Asphalt  pavements  Full-scale  tests  Parameters  Statistics  Viscoelasticity  Rheology  Predictions. Résumé : Rutting has an adverse effect on safety and riding comfort of pavement. Reliable prevention and prediction of rutting has been one of the major focuses in road research. This paper summarizes the methods available for rut depth prediction and performs a case study in two separate ways based on the data acquired from a full-scale indoor circular road test. One was to formulate the possible rut depth by integrating a four-element-five-parameter viscoelastic model and the layered strain approach. The other was based on an empirical method. It is verified that both methods are applicable in predicting rut depth within the near future after open to traffic. The empirical method, however, is also capable of predicting rut depth within the whole design life. And theoretical method proves inadequate because of the limitation of the model itself and also of the method for obtaining parameters. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Approaches to rut depth prediction in semirigid asphalt pavements [texte imprimé] / Jun Yang, Auteur ; Haizhu Lu, Auteur ; Haoran Zhu, Auteur . - pp. 510-516. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 510-516 Mots-clés : Asphalt  pavements  Full-scale  tests  Parameters  Statistics  Viscoelasticity  Rheology  Predictions. Résumé : Rutting has an adverse effect on safety and riding comfort of pavement. Reliable prevention and prediction of rutting has been one of the major focuses in road research. This paper summarizes the methods available for rut depth prediction and performs a case study in two separate ways based on the data acquired from a full-scale indoor circular road test. One was to formulate the possible rut depth by integrating a four-element-five-parameter viscoelastic model and the layered strain approach. The other was based on an empirical method. It is verified that both methods are applicable in predicting rut depth within the near future after open to traffic. The empirical method, however, is also capable of predicting rut depth within the whole design life. And theoretical method proves inadequate because of the limitation of the model itself and also of the method for obtaining parameters. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]

Base capacity of open-ended steel pipe piles in sand / Feng Yu in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1116–1128. Titre : Base capacity of open-ended steel pipe piles in sand Type de document : texte imprimé Auteurs : Feng Yu, Auteur ; Jun Yang, Auteur Année de publication : 2012 Article en page(s) : pp.1116–1128. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Steel  pipe  piles  Sand  Base  capacity  Soil  plugging  Cone  penetration  test  (CPT) Résumé : This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter—a key factor reflecting the influence of pile embedment—whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000667 [article] Base capacity of open-ended steel pipe piles in sand [texte imprimé] / Feng Yu, Auteur ; Jun Yang, Auteur . - 2012 . - pp.1116–1128. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1116–1128. Mots-clés : Steel  pipe  piles  Sand  Base  capacity  Soil  plugging  Cone  penetration  test  (CPT) Résumé : This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter—a key factor reflecting the influence of pile embedment—whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000667

Improved wear resistance of dendrite composite eutectic Fe-B alloy / Licai Fu in Transactions of the ASME . Journal of tribology, Vol. 133 N° 4 (Octobre 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 133 N° 4 (Octobre 2011) . - 05 p. Titre : Improved wear resistance of dendrite composite eutectic Fe-B alloy Type de document : texte imprimé Auteurs : Licai Fu, Auteur ; Jun Yang, Auteur ; Qinling Bi, Auteur Année de publication : 2012 Article en page(s) : 05 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Dendrites  Eutectic  alloys  Friction  Oxidation  Wear  resistance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The dry-sliding tribological properties of the dendrite composite eutectic Fe-B alloys (Fe94.3B5.7, Fe75B25 Fe67B33) were studied comparatively with various sliding speeds. The friction coefficient of the Fe-B alloy changes slightly with the boron content. The wear rate of the Fe94.3B5.7 alloy with about 30 vol. % dendrite t-Fe2B is only one third of Fe75B25 alloy with 15 vol. % dendrite and Fe67B33 alloy with 90 vol. % dendrite in the high sliding speed. First, a hard t-Fe2B phase reduced the wear of the Fe-B alloy directly. Second, the compactly oxide layers resulting from oxidation of the alpha-Fe on the worn surfaces also decreases the wear rate of Fe-B alloys. On the whole, the wear rate of the Fe94.3B5.7 is lower than Fe67B33 and Fe75B25. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Improved wear resistance of dendrite composite eutectic Fe-B alloy [texte imprimé] / Licai Fu, Auteur ; Jun Yang, Auteur ; Qinling Bi, Auteur . - 2012 . - 05 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 133 N° 4 (Octobre 2011) . - 05 p. Mots-clés : Dendrites  Eutectic  alloys  Friction  Oxidation  Wear  resistance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The dry-sliding tribological properties of the dendrite composite eutectic Fe-B alloys (Fe94.3B5.7, Fe75B25 Fe67B33) were studied comparatively with various sliding speeds. The friction coefficient of the Fe-B alloy changes slightly with the boron content. The wear rate of the Fe94.3B5.7 alloy with about 30 vol. % dendrite t-Fe2B is only one third of Fe75B25 alloy with 15 vol. % dendrite and Fe67B33 alloy with 90 vol. % dendrite in the high sliding speed. First, a hard t-Fe2B phase reduced the wear of the Fe-B alloy directly. Second, the compactly oxide layers resulting from oxidation of the alpha-Fe on the worn surfaces also decreases the wear rate of Fe-B alloys. On the whole, the wear rate of the Fe94.3B5.7 is lower than Fe67B33 and Fe75B25. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

Market power and optimal contract in delegated portfolio management / Jiliang Sheng in International journal of management science and engineering management, Vol. 5 N° 6 (Décembre 2010) 

Public ISBD [article]  in International journal of management science and engineering management > Vol. 5 N° 6 (Décembre 2010) . - pp.473-480 Titre : Market power and optimal contract in delegated portfolio management Type de document : texte imprimé Auteurs : Jiliang Sheng, Auteur ; Jun Yang, Auteur Année de publication : 2011 Article en page(s) : pp.473-480 Note générale : Management Langues : Anglais (eng) Mots-clés : Private  information  Market  power  Delegated  portfolio  management  Incentive  contract  Effort  cost Résumé : This article studies the contracting problem between an investor and a professional portfolio manager who possesses market power. The optimal linear contract is obtained in a closed form. When the manager has market power the contract affects the effort level of the manager, which provides a solution to the “non-incentive” result in Stoughton (1993) [30]. The sharing ratio of the portfolio return increases with effort cost, suggesting that a manager with a higher effort cost should be awarded a larger fraction of the investment profit. The sharing ratio also increases with the risk aversion of the portfolio manager. The optimal contract can separate different types of managers since only those with low effort costs would accept a contract when the sharing ratio is given. These findings compliment and extend the results in Stoughton (1993) [30] in which the manager does not have market power. DEWEY : 658 ISSN : 1750-9653 En ligne : http://www.ijmsem.org/OnlineJournal.do/?168.html [article] Market power and optimal contract in delegated portfolio management [texte imprimé] / Jiliang Sheng, Auteur ; Jun Yang, Auteur . - 2011 . - pp.473-480. Management Langues : Anglais (eng) in International journal of management science and engineering management > Vol. 5 N° 6 (Décembre 2010) . - pp.473-480 Mots-clés : Private  information  Market  power  Delegated  portfolio  management  Incentive  contract  Effort  cost Résumé : This article studies the contracting problem between an investor and a professional portfolio manager who possesses market power. The optimal linear contract is obtained in a closed form. When the manager has market power the contract affects the effort level of the manager, which provides a solution to the “non-incentive” result in Stoughton (1993) [30]. The sharing ratio of the portfolio return increases with effort cost, suggesting that a manager with a higher effort cost should be awarded a larger fraction of the investment profit. The sharing ratio also increases with the risk aversion of the portfolio manager. The optimal contract can separate different types of managers since only those with low effort costs would accept a contract when the sharing ratio is given. These findings compliment and extend the results in Stoughton (1993) [30] in which the manager does not have market power. DEWEY : 658 ISSN : 1750-9653 En ligne : http://www.ijmsem.org/OnlineJournal.do/?168.html

Supply chain performance under market valuation / Guoming Lai in Management science, Vol. 58 N° 10 (Octobre 2012) 

Public ISBD [article]  in Management science > Vol. 58 N° 10 (Octobre 2012) . - pp. 1933-1951 Titre : Supply chain performance under market valuation Type de document : texte imprimé Auteurs : Guoming Lai, Auteur ; Wenqiang Xiao, Auteur ; Jun Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 1933-1951 Note générale : Management Langues : Anglais (eng) Mots-clés : Supply  chain  Newsvendor  Capital  market  valuation Résumé : Based on a supply chain framework, we study the stocking decision of a downstream buyer who receives private demand information and has the incentive to influence her capital market valuation. We first characterize a market equilibrium under a general, single buyback contract. We show that the buyer's stocking decision can be distorted in equilibrium. Such a downstream stocking distortion hurts the buyer firm's own performance, and it also influences the performances of the supplier and the supply chain. We further reveal scenarios where full supply chain efficiency cannot be reached under any single buyback contract. Then, focusing on contract design, we characterize conditions under which a menu of buyback contracts can prevent downstream stocking distortion and restore full efficiency in the supply chain. Our study demonstrates that in a supply chain context, a firm's incentive to undertake real economic activities to influence capital market valuation can potentially be resolved through operational means. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/10/1933.abstract [article] Supply chain performance under market valuation [texte imprimé] / Guoming Lai, Auteur ; Wenqiang Xiao, Auteur ; Jun Yang, Auteur . - 2012 . - pp. 1933-1951. Management Langues : Anglais (eng) in Management science > Vol. 58 N° 10 (Octobre 2012) . - pp. 1933-1951 Mots-clés : Supply  chain  Newsvendor  Capital  market  valuation Résumé : Based on a supply chain framework, we study the stocking decision of a downstream buyer who receives private demand information and has the incentive to influence her capital market valuation. We first characterize a market equilibrium under a general, single buyback contract. We show that the buyer's stocking decision can be distorted in equilibrium. Such a downstream stocking distortion hurts the buyer firm's own performance, and it also influences the performances of the supplier and the supply chain. We further reveal scenarios where full supply chain efficiency cannot be reached under any single buyback contract. Then, focusing on contract design, we characterize conditions under which a menu of buyback contracts can prevent downstream stocking distortion and restore full efficiency in the supply chain. Our study demonstrates that in a supply chain context, a firm's incentive to undertake real economic activities to influence capital market valuation can potentially be resolved through operational means. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/10/1933.abstract

Timing of effort and reward / Jun Yang in Management science, Vol. 56 N° 9 (Septembre 2010) 

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