Land-tenure policy reforms: Decollectivization and the Doi Moi system in Vietnam

millions fed, food security, rice, Land tenure, Land reform, Doi Moi, Decollectivization,

Modelling cross-market linkages between global markets and China’s A-, B- and H-shares

One of the biggest challenges in quantifying joint risk and forming effective policies in financial management and investment strategies is to fully understand the characteristics of market associations in low and high volatility periods. Market interdependence, therefore, is a hot topic that has received interest from academics and industry experts, especially since the Asian Financial Crisis in 1997. China, being the world’s second-largest economy, has been the centre of many studies investigating stock market dependencies. While China has three major share types, namely A-, B- and H-shares, with different market players, market characteristics and operating efficiency, the number of studies on each of these share types remains conservative in comparison to the vast literature on the financial modelling of market interdependencies. Given the need for a more comprehensive understanding of the influence between these share types and other global markets, especially during market turbulences, this thesis examines the cross-market linkages between A-, B- and H-shares in China and several major emerging and advanced markets from 2002 to 2017, which is divided into two non-crisis periods and two crisis periods. This thesis assesses market integration among 17 markets, including asymmetries and leverage effect in the marginal distributions, volatility spillover and tail dependence. The thesis aims to: 1) investigate the univariate asymmetries and leverage effect in the distributional volatility of each time series and to detect volatility spillover between China and other studied markets; 2) assess the dynamic multivariate dependence between China and other studied markets; 3) evaluate the bivariate dependence structure for each of China’s markets and other studied markets using seven different copula functions; and 4) study the multivariate joint tail dependence structure of all studied markets using vine copulas. There are various findings from the thesis. Many advanced and emerging markets experienced leverage effect and asymmetries in volatility. China’s markets were much more prone to local shocks than external shocks and in many cases, there is evidence that China’s markets diverged from the global trends especially during the crisis periods. Besides, segmentation between China’s markets and the United States is clearly evident. In addition, regional dependence is stronger than intra-regional dependence. The thesis also found the existence of contagion effect between each of China’s markets and various markets in the sample in the Global Financial Crisis. Finally, heterogeneity was found for A-, B- and H-shares in various aspects, from distributional asymmetries to joint behaviour in both crisis and non-crisis periods. A novel aspect of this thesis is that it closes the gap in the literature of market linkages for A-, B- and H-shares with other global markets by assessing volatility spillover, time-varying co-movement, and tail dependence among the studied markets. This thesis provides various implications in both theoretical and empirical contexts in many areas including measuring joint risk at the tails, constructing an optimal portfolio, hedging, and managing financial exposures and contagious volatility from other markets. The thesis provides some recommendations and suggestions regarding the policies implemented in China

ハノイ市における埋戻し材としての繊維材混合流動化処理土の利用促進に関する研究

In this study, the applicability of Liquefied Stabilized Soil (LSS) mixed with the fibered material as the backfill materials at Hanoi city in Vietnam has been investigated. Research works including experiment and analysis have been conducted simultaneously aiming to promote the application of LSS in Hanoi city in the coming time. This study is summarized as follows. (1) The influence of slurry density on strength and deformation characteristics of LSS mixed with fibered material was evaluated. A series of Consolidated?Undrained triaxial compression tests with measured pore water (CUB tests) under the condition on an axial strain rate of 0.054%/min have been carried out for LSS mixed with fibered material amount of 0 and 10 kg/m3 at curing time of 28 and 56 days, respectively. Based on the test results, it was found that when the slurry density is slightly decreased from the appropriate slurry density, it is considered that the maximum deviator stress (qmax) decreased remarkably. In addition, it was found that the local damage caused by shearing even in the LSS mixed with fiber material prepared on the low slurry density is reduced by the effect of reinforcement on the fiber material. (2) The difference in triaxial shear property of LSS mixed with fiber material cured in laboratory and at field was investigated to be carried out a series of CUB tests for both specimens of LSS mixed with fiber material amount of 0 and 10 kg/m3 prepared by trimming LSS retrieved from a model ground by block sampling and cured in laboratory at curing time of 28 and 56 days, respectively. Based on the test results, it was found that the qmax in q~εa relations of LSS mixed with fiber material cured at field tend to be larger than that cured in laboratory. (3) A procedure for prediction of vehicle-induced vibration from a road surface has been established as a case study for a general road in Hanoi city in conformity with Vietnamese Standard. The vibration propagation from a road surface was analyzed by the 2-D FEM. The numerical results in terms of vibration velocity allow estimating the vibration velocity level, and then it is applicable to the prediction of vehicle-induced vibration. The calculated vibration velocity level on backfilling sandy soil indicated to be higher than the allowable threshold, therefore appropriate measures should be taken to decrease these vibrations. (4) According to the numerical analysis results on a mitigation of vehicle-induced vibration in case using LSS as backfill material by the established analysis method, it is found that the application of LSS can reduce the ground vibration. This will be a new advantage. Then, it is considered that the application to backfilling ground of LSS become one of effective measure for reduction of vehicle-induced vibration. Therefore, it is considered that the application of the LSS mixed with fibered material as backfilling material will be more promoted in Hanoi city.本研究は，ベトナム，ハノイ市での埋戻し材としての繊維材混合流動化処理土の適用性を検討したものである。今後，ベトナム，ハノイ市において，流動化処理土の適用を普及する目的で，実験および解析に関する研究が並行して実施された。本研究は，以下のように要約される。1) 繊維材混合流動化処理土の強度・変形特性に及ぼす泥水密度の影響について検討するために，軸ひずみ速度0.054 %/minの条件で一連の圧密非排水三軸圧縮試験（CUB試験）が，繊維材混合量0，10 kg/m3，養生日数28，56日の繊維材混合流動化処理土に対して実施された。試験結果から，泥水密度が適切な泥水密度よりわずかに減少すると，最大軸差応力qmaxが顕著に減少すると考えられることが明らかにされた。さらに，低泥水密度で作製された繊維材混合流動化処理土でも，繊維材の補強効果で，せん断中にもたらされる局所的な損傷が減少することが明らかにされた。2) 繊維材をそれぞれ，0，10 kg/m3で添加し，養生日数を28，58日として作製された室内および原位置供試体による繊維質材料混合流動化処理土の三軸せん断特性の比較・検討を行った。原位置供試体は，モデル地盤からブロックサンプリングにより採取して作製され，室内供試体は原位置供試体と同じバッチで室内養生して作製された。一連のCUB試験を実施した結果，繊維質材料混合流動化処理土のq～εa関係のqmaxは，室内養生供試体に比べ，現場養生供試体のほうが概ね大きくなる傾向にあることが明らかとなった。3) ベトナム基準に準拠したハノイ市の一般的な道路を事例として，道路表面から伝播する車両振動の予測手法を提案した。道路表面からの振動伝播は，2次元FEMにより解析された。計算結果より，振動速度から振動速度レベルを評価することが可能であり，提案手法が車両振動予測に適用可能であることが明らかにされた。また，埋戻し砂質土に対して計算された振動速度レベルは，許容値より大きくなることが示されたことから，振動軽減のための適切な対策が必要となることが明らかにされた。4) 提案された解析手法により，埋戻し材として流動化処理土を用いた場合の車両振動の軽減に対する数値計算結果によれば，流動化処理土の適用が地盤振動を軽減させ得ることが明らかとなった。これは，流動化処理土の適用方法における新たな利点であり，流動化処理土の埋戻し地盤への適用は，車両振動の軽減に対する有効な対策の一つになると考えられる。以上より，ハノイ市における埋戻し材としての繊維材混合流動化処理土の利用促進が期待できる方法が示されたと考える。室蘭工業大学 (Muroran Institute of Technology)博士（工学

EFFECTS OF GUIDING CHAMBER ON WELDING PRESSURE IN HOLLOW EXTRUSION DIE DESIGN OF AA7075

Porthole die extrusion has a great advantage in the forming of hollow section of aluminum alloy tube. This paper aims at the development of an extruding seam square tube of AA7075 high strength aluminum alloy. In order to increase the welding pressure of the hollow AA7075 tube in extrusion process, a special die feature has been created. Several different proportions of chamber structure in outlet of extrusion die have been designed. The finite element analysis software DEFORM 3D to analyze various design parameters on the load – displacement and the welding pressure have been studied. In this study, a different high proportion in material guiding chamber has been defined. The results showed that if a suitable material guiding chamber has been built then welding pressure can be increased rapidly. When the ratio of chamber height and length is 2:1 the increased welding pressure is the best

A note on the width of sparse random graphs

In this note, we consider the width of a supercritical random graph according to some commonly studied width measures. We give short, direct proofs of results of Lee, Lee and Oum, and of Perarnau and Serra, on the rank- and tree-width of the random graph $G(n,p)$ when $p= \frac{1+\epsilon}{n}$ for $\epsilon > 0$ constant. Our proofs avoid the use, as a black box, of a result of Benjamini, Kozma and Wormald on the expansion properties of the giant component in this regime, and so as a further benefit we obtain explicit bounds on the dependence of these results on $\epsilon$. Finally, we also consider the width of the random graph in the weakly supercritical regime, where $\epsilon = o(1)$ and $\epsilon^3n \to \infty$. In this regime, we determine, up to a constant multiplicative factor, the rank- and tree-width of $G(n,p)$ as a function of $n$ and $\epsilon$.Comment: 18 page

Effect of blue light on the photosynthesis and flavonoid accumulation in leaves of Hedyotis corymbosa (L.) Lam.

In plants, blue light with a short wavelength can promote light reaction in photosynthesis and increase dry mass. Photosynthesis plays an important role in supporting carbohydrates for primary and secondary metabolism processes. Flavonoids are phenolic compounds, a class of plant secondary metabolites, that can be obtained from many medicinal herbs. These phenolic compounds are involved in the reactive oxygen species scavenging system, inhibit lipid peroxidation by free-radical, chelate redox-active metals resulting in their antioxidant ability and cardioprotective effects. In this study, H. corymbosa (L.) Lam., one of the common medicinal herbs, was cultured for 4 weeks under conditions of 450 nm blue LED (light-emitting diode) lights at the different light intensity as treatments and fluorescent lamp light as a control to investigate the effects of blue light on photosynthesis and flavonoid accumulation in leaves. The results show that blue light at 450 nm promoted photosynthetic rate by enhancing stomatal opening, electron transport rate in light reaction. Blue light also enhanced photoprotection by decrease the quantum yield of non-photochemical losses, increase the quantum yield of non-photochemical quenching and gained 24% more in dry mass. The accumulation of flavonoid and total phenolic compounds in leaves was followed by a decrease in sucrose. These events proved that blue light enhances photosynthesis and increase carbohydrate and flavonoid accumulation in leaves

The Happy Farmer:Self-Employment and Subjective Well-Being in Rural Vietnam

Using a unique survey data set this paper documents a positive effect of self-employment in farming on subjective well-being. This direct effect is only partly offset by negative, indirect effects working through income and other variables. These findings are interpreted as effects of self-employment in farming on perceived autonomy, competence and relatedness. The results suggest that economic transformation is associated with a psychological cost, which may contribute to explaining earnings gaps between sectors and types of employment. We also investigate other determinants of happiness, and for example find strong positive effects of own income and strong negative effects of neighbors’ income, suggesting the importance of relative rather than absolute levels of income