The first chapter of this dissertation explores the impact of export quality on the exports of a developing and a developed country. We developed a theoretical framework using the two-country oligopolistic model with quality differentials in product. We find that enhancing export quality improves export performance of a country but it reduces domestic trade under certain conditions. In the second chapter, we test the theoretical findings of Chapter 1 empirically, using annual inter-country and intra-country trade data for 142 countries from 1963 to 2014 and by applying the gravity model of trade. We also use IMF’s Export Quality Index and Unit Value of exports to estimate a two-stage gravity model to examine the effects of producer prices and exports quality on both exports and domestic trade. Our empirical findings are consistent with our theoretical predictions. The empirical findings suggest that quality has a positive impact on international trade and a 1% increase in quality leads to an increase in total exports by 1.08%. A 1% increase in quality leads to a fall in intranational trade by 2.69%. The effect of improving export quality on the exports is more pronounced for OECD countries than the non-OECD countries. This study also discusses the policy measures that developing countries should take to compete effectively in the international market and break the cycle of over-reliance on low-quality export goods and achieve higher economic growth.The third chapter explores the impact of export quality on carbon emissions and fossil fuel energy use. We estimated an OLS with fixed effects and conducted a 2SLS analysis using data for 163 countries from 1980–2014. We have found a positiveassociation between export product quality upgrading and fossil fuel consumption for non-OECD member countries and a negative association for OECD member countries. A 1% increase in export quality increases fossil fuel consumption by 0.092% in non-OECD countries and reduces fossil fuel consumption by 1.57% in OECD countries. Similarly, we also found a positive association between export product quality upgrading and carbon emissions for non-OECD member countries and a negative association for OECD countries. A 1% increase in export quality increases carbon emissions by 0.139% in non-OECD countries and reduces carbon emissions by 1.327% in OECD countries. Our results also indicate that the Environmental Kuznets Curve (EKC) hypothesis is valid.

八十年代，隨著總體經濟的失衡，國內之出口結構也起了重大的變化；值得注意的是中間產品以及機器設備比重的增加，以及非耐久消費財比重的減少。本研究的研究對象為民國七十年到八十二年我國製造業的出口情形，觀察出口結構與出口品質的變化，根據Falvey(1981)與Flam & Helpman(1987)建立實證模型，分別估計這些模型並進行Non-nested之假設。本研究的結論如下：一、在出口結構方面高勞動密集財之出口有逐年下降之趨勢，而高資本與高技術密集財則有逐年上升之趨勢，顯示我國之出口結構已慢慢轉向資本與技術密集。二、出口結構之決定因素勞動密集財出口比例之變化與國內要素稟賦，如固定資本、人力資本以及勞動的關係較為密切；資本密集財的出口因素用Ricardian理論或H-O理論來解釋都不是很完全；而技術密集財的出口決定因素則與相對成本和技術變動的關係較為密切，這些我國出口情形的實證結果與過去之文獻結果恰可以相呼應。三、在出口品質方面我國製造業的出口品質有逐年上升的趨勢，其主要決定因素為相對勞動成本之上升，以及技術之變動，而與要素稟賦之關係較不密切。

Cette thèse se compose de trois chapitres ayant en commun la question de la qualité des exportations dans un contexte de pays en voie de développement. La thèse s’intéresse plus particulièrement à différents aspects permettant d’améliorer le niveau de qualité des exportations. Le premier chapitre est consacré à l'impact de l'Aide au commerce (Aid for trade) sur la qualité des exportations des pays récipiendaires. Il suggère un effet positif de la politique d'aide au commerce sur la qualité des exportations. Le deuxième chapitre porte sur le rôle de vérification de la qualité joué par les intermédiaires dans le commerce international. Les résultats indiquent que seuls les intermédiaires spécialisés jouent ce rôle. Le troisième chapitre examine le lien entre l'orientation à l'exportation des entreprises et leur performance en matière d'innovation. L’analyse empirique met en évidence une réduction des investissements en R&D chez les exportateurs dont les ventes s’orientent principalement vers les exportations au détriment du marché intérieur et ce d’autant plus qu’ils font face à une incertitude élevée de la demande. Ces évolutions défavorables pourraient être surmontées néanmoins si l’entreprise a une riche expérience commerciale ou une productivité élevée. Les trois résultats principaux de cette thèse sont ainsi que l'aide au commerce ainsi que l’essor d’intermédiaires de type spécialisé contribuent à la montée en qualité des exportateurs tandis que l'incertitude de la demande extérieure tend à l’inverse à entraver l’innovation des firmes exportatrices. / This thesis is composed of three chapters that have in common the question of export quality in a developing country context. The thesis focuses on different aspects of improving the quality level of exports. The first chapter is devoted to the impact of Aid for Trade on the quality of exports from recipient countries. It suggests a positive effect of Aid for Trade policy on the quality of exports. The second chapter focuses on the quality assurance role played by intermediaries in international trade. The results indicate that only specialized intermediaries play this role. The third chapter examines the link between firms' export orientation and their innovation performance. The empirical analysis shows a reduction in R&D investment by exporters whose sales reorient towards exports to the detriment of the domestic market, especially as they face high demand uncertainty. These unfavourable developments could nevertheless be overcome if the company has a long trade experience or high productivity. The three main results of this thesis are that aid for trade and the rise of specialized intermediaries contribute to the rise in quality of exporters, while the uncertainty of external demand tends, on the other hand, to hinder innovation by exporting firms.