Dynamic mechanism design for markets with strategic resources

The assignment of tasks to multiple resources becomes an interesting game theoretic problem, when both the task owner and the resources are strategic. In the classical, nonstrategic setting, where the states of the tasks and resources are observable by the controller, this problem is that of finding an optimal policy for a Markov decision process (MDP). When the states are held by strategic agents, the problem of an efficient task allocation extends beyond that of solving an MDP and becomes that of designing a mechanism. Motivated by this fact, we propose a general mechanism which decides on an allocation rule for the tasks and resources and a payment rule to incentivize agents' participation and truthful reports. In contrast to related dynamic strategic control problems studied in recent literature, the problem studied here has interdependent values: the benefit of an allocation to the task owner is not simply a function of the characteristics of the task itself and the allocation, but also of the state of the resources. We introduce a dynamic extension of Mezzetti's two phase mechanism for interdependent valuations. In this changed setting, the proposed dynamic mechanism is efficient, within period ex-post incentive compatible, and within period ex-post individually rational.

The land hoarding and land inspector dilemma in China : an evolutionary game theoretic perspective

China has experienced considerable economic growth since 1978, which was accompanied by unprecedented growth in urbanization and, more recently, by associated rising urban housing and land banking issues. One such issue is that of land hoarding - where real estate developers purchase land to hold unused in the rising market for a future lucrative sale, often several years later. This practice is outlawed in China, where land use is controlled by increasingly strengthened Government policies and inspectors. Despite this, land hoarding continues apace, with the main culprits being the developers and inspectors working subversively. This resembles a game between two players - the inspector and the developer - which provides the setting for this paper in developing an evolutionary game theory model to provide insights into dealing with the dilemmas faced by the players. The logic and dilemma of land banking strategy and illegal land banking issues are analysed, along with the land inspector’s role from a game theory perspective by determining the replication dynamic mechanism and evolutionary stable strategies under the various conditions that the players face. The major factors influencing the actions of land inspectors, on the other hand, are the costs of inspection, no matter if it is strict or indolent, conflict costs, and income and penalties from corruption. From this, it is shown that, when the net loss for corruption (income from corruption minus the penalties for corruption and cost of strict inspections) is less than the cost of strict inspections, the final evolutionary stable strategy of the inspectors is to carry out indolent inspections. Then, whether penalising developers for hoarding is severe or not, the evolutionary strategy for the developer is to hoard. The implications for land use control mechanisms and associated developer-inspector actions and counteractions are then examined in the light of the model's properties.

Sediment incipience in turbulence generated in a square tank by a vertically oscillating grid

The failure of hydraulic structures in many estuaries and coastal regions around the world has been attributed to sediment transport and local scour. The sediment incipience in homogenous turbulence generated by oscillating grid is studied in this paper. The turbulent flow is measured by particle tracer velocimetry (PTV) technique. The integral length scale and time scale of turbulence are obtained. The turbulent flow near the wall is measured by local optical magnification. The sediment incipience is described by static theory. The relationship of probability of sediment incipience and the turbulent kinetic energy were obtained experimentally and theoretically. The distribution of the turbulent kinetic energy near the wall is found to obey the power law and the turbulent energy is further identified as the dynamic mechanism of sediment incipience.

Multi-hit ballistic damage characterisation of 304 stainless steel plates with finite elements

Multi-impact of projectiles on thin 304 stainless steel plates is investigated to assess the degradation of ballistic performance, and to characterise the inherent mechanisms. Assessment of ballistic degradation is by means of a double-impact of rigid spheres at the same site on a circular clamped plate. The limiting velocity of the second impact, will be altered by the velocity of the antecedent impact. Finite element analyses were used to elucidate experimental results and understand the underlying mechanisms that give rise to the performance degradation. The effect of strength and ductility on the single and multi-impact performance was also considered. The model captured the experimental results with excellent agreement. Moreover, the material parameters used within the model were exclusively obtained from published works with no fitting or calibration required. An attempt is made to quantify the elevation of the ballistic limit of thin plates by the dynamic mechanism of travelling hinges. Key conclusions: The multi-hit performance scales linearly with the single-hit performance; and strength is a significantly greater effector of increased ballistic limit than ductility, even at the expense of toughness. © 2014 Elsevier Ltd.

Study on pulsed laser ablation and deposition of ZnO thin films by L-MBE

ZnO, as a wide-band gap semiconductor, has recently become a new research focus in the field of ultraviolet optoelectronic semiconductors. Laser molecular beam epitaxy (L-MBE) is quite useful for the unit cell layer-by-layer epitaxial growth of zinc oxide thin films from the sintered ceramic target. The ZnO ceramic target with high purity was ablated by KrF laser pulses in an ultra high vacuum to deposit ZnO thin film during the process of L-MBE. It is found that the deposition rate of ZnO thin film by L-MBE is much lower than that by conventional pulsed laser deposition (PLD). Based on the experimental phenomena in the ZnO thin film growth process and the thermal-controlling mechanism of the nanosecond (ns) pulsed laser ablation of ZnO ceramic target, the suggested effective ablating time during the pulse duration can explain the very low deposition rate of the ZnO film by L-MBE. The unique dynamic mechanism for growing ZnO thin film is analyzed. Both the high energy of the deposition species and the low growth rate of the film are really beneficial for the L-MBE growth of the ZnO thin film with high crystallinity at low temperature.

Diagnostic experiments for transport mechanisms of suspended sediment discharged from the Yellow River in the Bohai Sea

Five diagnostic experiments with a 3D baroclinic hydrodynamic and sediment transport model ECOMSED in couple with the third generation wave model SWAN and the Grant-Madsen bottom boundary layer model driven by the monthly sediment load of the Yellow River, were conducted to separately diagnose effects of different hydrodynamic factors on transport of suspended sediment discharged from the Yellow River in the Bohai Sea. Both transport and spatio-temporal distribution of suspended sediment concentration in the Bohai Sea were numerially simulated. It could be concluded that suspended sediment discharged from the Yellow River cannot be delivered in long distance under the condition of tidal current. Almost all of sediments from the Yellow River are deposited outside the delta under the condition of wind-driven current, and only very small of them are transported faraway. On the basis of wind forcing, sediments from the Yellow River are mainly transported north-northwestward, and others which are first delivered to the Laizhou Bay are continuously moved northward. An obvious 3D structure characteristic of sediment transport is produced in the wind-driven and tide-induced residual circulation condition. Transport patterns at all layers are generally consistent with circulation structure, but there is apparent deviation between the depth-averaged sediment flux and the circulation structure. The phase of temporal variation of sediment concentration is consistent with that of the bottom shear stress, both of which are proved to have a ten-day cycle in wave and current condition.

Study on the energy transfer between UO22+ and Eu3+ in sol-gel derived titania matrix by luminescence spectroscopy

The TiO2 gel doped with UO22+ and Eu3+ has been prepared by a sol-gel method. The quenching of the UO22+ emission by Eu3+ and the energy transfer from the excited state of UO22+ to the ground state oh Eu3+ have been investigated. The energy transfer has been studied by the measurement of luminescence lifetime tau, calculations of energy transfer efficiency eta(ET) and energy transfer rate W-ET The experimental results indicated that the quenching is combined static and dynamic mechanism, but the static mechanism is dominant.

Tectonic Evolution and Dynamics of Deepwater Area of Pearl River Mouth Basin, Northern South China Sea

Quantitative studies on the evolution and dynamics of the deepwater area of Pearl River Mouth basin (PRMB) were carried out based on the latest geological and seismic data. The study area is generally in an extensional state during the Cenozoic. The major extension happened in the earlier syn-rift stages before 23 Ma and the extension after 23 Ma is negligible. Two rapid subsidence periods, 32-23 Ma and 5.3-2.6 Ma, are identified, which are related to the abrupt heat decay during margin breakup and the collision between the Philippine Sea plate and the Eurasian plate, respectively. The strongest crustal thinning in the Baiyun (sic) sag may trigger the syn-rift volcanism along the weak faulted belt around the sag. The Cenozoic tectonic evolution of the study area could be divided into five stages: rifting (similar to 50-40 Ma), rift-drift transition (similar to 40-32 Ma), early post-breakup (similar to 32-23 Ma), thermal subsidence (similar to 23-5.3 Ma) and neotectonic movement (similar to 5.3-0 Ma).

Characteristics of low-frequency components of the near-bottom current in the Chinese Pioneer Area

Two deep-sea moorings were deployed respectively in the east area and the west area of Chinese Pioneer Area (CPA) in the tropic east Pacific to monitor the regional deep-sea dynamics below 600 meters above bottom (mab) from July 1997 to Oct. 1999. Results of statistics, spectral estimate and correlation analysis of the low-passed velocity data show that time scales of low-frequency components of the near-bottom currents are 25similar to120 days, in which 51-day period dominates the lower band of the frequency domain. Topographic features have obvious effect on low-frequency currents below 50 mab; modulations of the bottom-intensified sheared mean flow to the low-frequency currents are the dynamic mechanism of the frequency shift that occurs in both the east-area and the west-area.

源区黑潮季节变异及其动力机制的数值研究

黑潮是太平洋区域的一支强劲的西边界流，在流经吕宋海峡时，流态发生显著变化。黑潮具有高温、高盐、高流速的特征，它的季节变化和年际变化对我国近海的环流结构和温盐分布起到了决定性的作用。 由于吕宋海峡现场观测资料的匮乏，关于源区黑潮的季节性变化和动力机制，众说纷纭。本文在前人研究的基础上，应用POM模型的POM2K版本，构建了一个以太平洋海盆为研究区域的三维斜压模型，模型采用正交曲线网格，在中国海区域进行加密并较好的拟合了岸线。 模式的结果较好的再现了东中国海和南海的主要流系及其季节性变化特征，如黑潮、台湾暖流、对马暖流等。东中国海的几处关键断面流量同实测资料具有较高的一致性，表明模式具有较高的可信度，之后讨论了南海海表面高度异常及其与卫星高度计的比较，结果再次验证了模式的可信度。 接着本文探讨了北赤道流分岔位置季节性的变化对源区黑潮流量的影响，结果表明，秋冬季节北赤道流分岔的位置较靠北，源区黑潮流量较大，而春夏季节北赤道流分岔位置较靠南，黑潮流量较小。 在此基础上，进行了几组数值实验，来研究源区黑潮的动力机制，结果显示，风应力的季节性变化是造成吕宋海峡净流量季节变化的主要驱动力，也是造成上层流场季节变化的主要因素；非线性作用对吕宋海峡的净流量的季节变化无多大贡献，但对上层流场的影响显著；黑潮在吕宋海峡处的强斜压性常年存在，吕宋海峡的净流量和上层流场对斜压梯度力的计算方案较敏感。

浅海贝藻养殖水域沉积物再悬浮的发生机制及生态效应

沉积物再悬浮作为一个比较普遍的物理现象，对浅海生态系统污染物的生物地球化学循环具有强烈的干扰作用。本研究以我国北方重要养殖海湾——桑沟湾为研究对象，从物理、化学、生物三个角度出发，研究了沉积物再悬浮的发生过程以及再悬浮介质-沉积物的源汇转换角色及其与养殖藻类的关系，构建了波流耦合模型和再悬浮颗粒物浓度预测数学模型。主要研究结果如下： 1）桑沟湾的海湾动力比约为1.54，沉积物具有发生再悬浮的潜在动力条件；推导出波流耦合切应力的计算公式。 2）悬浮颗粒物浓度（SSC）与浊度（NTU）之间符合线性方程SSC=15.908×ln（NTU）+7.0888（n＝33，R2＝0.7209）；碎屑有机碳库是桑沟湾养殖生态系统中最大的有机碳库，占总POC库储量的81.87%。 3）沉积物再悬浮的临界切应力在0.059 N/m2左右，耦合切应力与悬浮颗粒物浓度符合方程= 238.06 SSC + 25.215（n=25，R2 = 0.7298）；最大剪切深度可达8.81 cm；桑沟湾沉积物再悬浮通量的数量级在10-5~10-6 kg·m-2·s-1之间，再悬浮临界风速约为5.51 m/s，全年约有171天沉积物处于再悬浮状态；构建了沉积物再悬浮颗粒物浓度预测数学模型。 4）桑沟湾表层沉积物总氮的含量范围313.09~1094.44µg/g，有机氮是总氮的主要形态，平均占总氮的60.86%；交换态氮是无机氮的主要形式，平均占无机氮的71.40%，交换态氮中NO3--N的含量最大；桑沟湾表层沉积物的TOC/TN比值为9.38，表明沉积物中有机质具有混合来源的特征；无机磷是桑沟湾表层沉积物中磷的主要形态，平均占总磷的73.33%，钙结合磷是无机磷的主要赋存形态；表层沉积物中潜在生物有效性磷的含量占总磷的86.54%，具有很强的释磷潜力。桑沟湾重金属的潜在生态危害指数RI约为36.17，表明重金属的潜在生态危害轻微。 5）再悬浮过程中沉积物春季表现为氮磷源，释放溶解无机氮和磷酸盐；夏、秋季表现为氮汇磷源，释放磷酸盐而吸附溶解无机氮；冬季表现为氮磷汇，吸附磷酸盐和溶解无机氮。

若干大洋西边界潜流的分布特征及其形成机制

大洋环流是海盆尺度上海水的持久流动，是海洋中质量、热量输运的主要通道，对全球气候变化有重要影响。经过二十年来的大量调查研究，对海洋上层的风生大洋环流有了比较充分的认识。然而，近几十年来的大量观测显示，大洋环流的垂直结构并非像传统认识的那样单一，在很多区域存在与之反向的次表层潜流，如北赤道流（NEC）下方的北赤道逆流（NEUC）、棉兰老海流（MC）下方的棉兰老潜流（MUC），吕宋岛附近黑潮（KC）下方的吕宋潜流（LUC），东澳大利亚海流（EAC）下方的大堡礁潜流（GBRUC）和东澳大利亚潜流（EAUC），阿加勒斯海流（AC）下方的阿加勒斯潜流（AUC）等。这些潜流一般分布在西边界，或者在西边界处增强，称为“西边界潜流（WBUC）”。与表层环流相比，对次表层潜流的结构和形成机制认识不足，因此利用不断更新的各种实测数据和高分辨率同化数据，通过理论分析和数值试验，探讨研究次表层潜流的分布特征和形成机制，对于大洋环流动力学理论的进一步发展具有重要的科学意义。 本文利用中国ARGO资料中心提供的ARGO资料、全球简单海洋资料同化分析系统产生的SODA同化资料和日本地球模拟器模拟出来的OFES资料，分析了北太平洋潜流（NEUC、MUC和LUC）、南太平洋潜流（GBRUC和EAUC）和南印度洋潜流（AUC）的时间和空间分布特征，并基于温跃层以下转向的地转判据分析了其形成机制。主要结果如下： （1）在菲律宾以东海域，表层的NEC在12N附近的西边界分叉，形成向北的KC和向南的MC。在400-800米左右棉兰老岛东侧128E-130E处出现与上层海流方向相反的潜流MUC，MUC在9N和12N附近转向东并分成2支，汇入NEC下方的2支并行向东流的NEUC。到了1000米左右，吕宋岛东侧122E-124E处出现LUC，而MUC也有向岸的趋势，限制在127E以西的范围，两者在12Ｎ附近相遇，然后转向东汇入NEUC。随着深度的加深，NEUC的北侧分支流轴向北偏移。从SODA资料和OFES资料在8N、18N和138E断面的气候态年平均和月平均温度剖面可以很清晰的看出，温跃层分别呈现东高西低、西高东低和南高北低的趋势，这与各个断面上表层流和次表层逆流之间等值线倾斜方向一致。从月平均的速度剖面可以看出，MC一般位于600db以上，600db以下出现北向次表层潜流MUC，MUC春夏较强，秋冬较弱；KC一般位于500db以上，个别月份深入到2000db，其下方均有南向的LUC出现，LUC春夏较弱，秋冬较强；上层西向NEC的主体一般位于400db以上，其下方均有东向的NEUC出现，NEUC春夏较强，秋冬较弱。 在北太平洋菲律宾以东海域，同时满足两个判据的区域与潜流的发生区域符合情况较好，唯一的不同在于LUC汇入NEUC的区域没有同时满足两个判据。这是由于在吕宋岛和棉兰老岛东侧，海底地形较为陡峭，海流情况较为清晰，沿岸涡较少，而且在此区域内温跃层较浅，这些都为形成温跃层以下的地转流反向提供了充分的条件。 （2）在澳大利亚以东海域，表层的南赤道流（SEC）在澳大利亚东岸15S附近分叉，分为向北的北昆士兰海流（NQC）和向南的东澳大利亚海流（EAC）。500m-1000m，23S附近出现一支北向的次表层海流，沿着澳大利亚陆坡经过大堡礁抵达巴布亚新几内亚沿岸转向东，汇入新几内亚沿岸潜流（NGCUC），这支海流就是大堡礁潜流（GBRUC）。1000m-2000m，SEC下方15S附近出现东向的逆流。在2000m以下，由于地形的影响，海流局限在几个不连续的部分，而且流型较乱。从SODA资料和OFES资料在18S和30S断面的气候态年平均和月平均温度剖面可以很清晰的看出，温跃层均呈现西高东低的趋势。在18S，南向的EAC一般位于400db以上，其下方均有持续的GBRUC出现，一般有两个中心，春夏季较强，秋冬季较弱。在30S断面，EAC一般存在于2000db以上，其下方的次表层流并不规则。从此海域的气候态月平均分布来看，在大多月份没有北向的逆流存在，这说明其下方的次表层逆流并不是一个常年存在的现象。 在南太平洋，同时满足两个判据的区域包括SEC下方逆流的发生区域和澳大利亚东岸的沿岸区域，这些区域部分与潜流的发生区域符合较好，只是在30S左右并没有发生潜流的区域也同时满足判据。这是由于在30S附近，温跃层较深，导致了地转流较深，同时此区域内海底地形变化比较大，虽然在此位置形成了逆向的地转流，但是因为地形的限制，在此区域内不能形成有体系的逆流。 （3）在西南印度洋，SEC在非洲东岸分叉，形成一支源于25S的西南向海流——AC，这支海流平均流速达90cm/s左右，最大速度超过140cm/s。在其下方2000m左右，从35S开始在岸边出现东北向逆流——AUC，速度较小，仅为2cm/s左右。从31S、33S和35S断面的气候态年平均温度断面可以很清晰的看出，温跃层明显呈现西高东低的趋势。从月平均经向流速断面可以看出，在各个月份AC下方均出现不同强度的AUC，AC和AUC之间的等值线倾斜方向与温跃层的倾斜方向一致。 在南印度洋，满足判据的区域包括南非沿岸AUC的发生区域和南非东南的部分海域，南非沿岸的AUC紧靠岸边且深度较深，这是因为此区域内温跃层较深，导致形成的地转流位置较深，而形成的逆流由于与海底的摩擦而大大削弱。南非东南部分海域满足判据，大概是由于此区域海流比较复杂，而且此海域多涡。 表面风应力的强迫以及风生环流的斜压调整，使得潜流所在海域的海平面高度和温跃层倾斜方向相反，热带流涡和副热带流涡西向强化加强了该海域温跃层的倾斜程度，从而导致了次表层地转流反向。因此，大洋中次表层潜流是大洋斜压风生环流不可缺少的重要部分。但是在不同的海域存在不同的地形分布和海流分布，所以此理论只在某些合适的区域得到很好的体现。

东海南部流-涡结构分析与动力机制研究

东海作为全球海洋变化中最为敏感的海区之一，其环流变异不仅直接影响东亚和我国的气候，还关系到海区内营养盐的输运和污染物的净化。鉴于东海环流在中国近海环境和海上工程、海洋活动所起的重要作用，其研究是我国海洋工作者工作的重点。 31N以南的东海南部海域是水文调查最为丰富的海域，目前已经积累了超过8 000 000个站点水文数据（温度、盐度）和12 000 000站点流数据（流速、流向），这些数据为该海域的物理海洋学研究提供了坚实的物质基础。本文以东海南部海域的流-涡结构为研究对象，以丰富的观测资料为基础，辅以MASNUM浪-潮-流耦合模式，通过数据分析、模式验证和动力机制分析相结合的方法，明确东海南部海域存在的各个海流系和涡旋结构。 本文研究内容主要包括东海黑潮的流速结构及其时间变化特征、黑潮分支和海温之间的关系、黑潮右侧逆流的季节特征、黑潮左侧逆流的存在性验证、东海黑潮环流子系统的构成、台湾海峡内海流的路径和流量、台湾暖流的水体来源和路径、涡旋和冷（暖）中心的季节分布特征。

油田高含水期剩余油分布规律研究

After systemic investigation of the techniques，route lines and mechanisms about the remaining oil，the dynamic migration and congregation behavior of the remaining oil are discussed on base of interaction between flowing and enriching of water and oil.After the micro-scope modeling of the fluid flow in porous media and the changes in petrol-physical properties of the flowing system, the characters of fluid fields and the dynamic distribution of oil are discussed, among which the preference-flowing is focused on. Based on the preference-flowing in porous media, the concept of the preference-flowing channels is developed. According to above, heterogeneous distribution of water and oil in the field and dynamic mechanism of remaining oil are all obvious. media can be divided into three kinds, directional, stochastic, arbitrary porous media. The main research results are as following: 1. Treating the characteristic parameters such as permeability, porosity and wettability as regional parameter, the fluid field with high water-cut has been established by geostatistical method, among which the difference of flowing pores and the changes of its petrol-physical properties during flooding are studied. 2. The flow process of water and oil are recurrent in physical simulation experiments, in which the mechanisms and phenomena are caught and analyzed. Fluid flow mechanics in porous media with preference-flowing channels have been studied. 3. The mutual coupling between water and oil is induced and the mathematical evolution equations including this interaction were built. . 4. Through coupling effect between flowing water and oil, the dynamic migration and congregation behavior of remaining oil depend upon this coupling. 5. Coupling between water and oil act as driving force and trapping force for the remaining oil. The coupling model of thesis has been verified by simplified the numerical model and compared results with Ng35 oil reservoir in Gudao oil field, it has important theoretical and application values for improving precision of remaining oil and production performance prediction, and is a new method for studying the mechanics of remaining oil in channeled porous media has been established. Key words：flow field，high water-cut，coupling，dominant flow in porous media，remaining oil