An Analysis of Trade Patterns and the Effects of the Real Exchange Rate Movements in East Asia

This article investigates the patterns of vertical specialization in trade among China, Japan and Korea, and the effects of real exchange rate fluctuations under a multistage production process. By extending the models of Yi (2003, 2010), we derive two distinct features of vertical specialization and test them using Time-Varying Parameter (TVP) VAR. We find that a positive shock to China’s final good consumption increases the intermediate goods trade between Korea and China, with expanding magnitude over time. In addition, the positive effect of a real exchange rate depreciation on intermediate goods trade is strengthened through the competitiveness-enhancing channel, with this effect being more pronouncing in Korea-China trade than in Korea-Japan trade.     

多级斜坡路基软弱地基变形机理和稳定性数值分析

山区公路路基往往是在斜坡上填筑的,这种填筑形式更易于发生变形破坏,故本文以某斜坡路基为研究对象,研究斜坡路基地基变形机理,并用强度折减法分析该斜坡路基的稳定性。结果表明:①地基形变的总体趋势以沉降变形为主,随填筑高度的增加,水平位移逐渐趋于均匀,并表现为侧向外鼓,沉降最大值集中在与填筑体中心相交的区域。②路基中心的最终沉降位移相较于坡脚的2倍;路基整体有向斜坡下滑移的趋势;短坡脚的水平位移发展最快。③斜坡路基随填筑高度的增加,从深层滑动发展为浅层滑动,滑体集中于长坡脚。④随填筑高度的增加,安全系数逐渐降低。     

Designing communication architectures for interorganizational multimedia collaboration

Advances in computer and communication technologies have stimulated the integration of digital video and audio with computing, leading to the development of various computer‐assisted collaborations. In this article, we propose a multilevel conferencing paradigm called super conference for supporting collaborative interactions between geographically separated groups of users, with each group belonging to possibly a different organization. In a super conference, each participant must receive and display the composite media stream obtained by mixing media streams transmitted by all the other participants. Hierarchical communication architectures are naturally suited for media mixing in super conferences. We present algorithms for designing hierarchical mixing architectures that optimize real‐time end‐to‐end delays of media. In order to improve their real‐time performance further, we propose multistage mixing techniques by which mixers can carry out mixing concurrently with communication. Surprisingly, the optimal architectures for multistage mixing are widely different from those of monostage mixing (in which, mixing and media communication sequential as opposed to concurrent). Based on real‐time delay constraints of multimedia, we obtain interesting limits on the sizes of both super conferences and groups within super conferences in optimal hierarchical architectures, which go to show their high scalability in terms of both the maximum number of participants and the geographical separation between them.

At the Multimedia Laboratory at the University of California, San Diego, we have implemented a conferencing system on an environment of Sun SPARCstations equipped with digital multimedia hardware. As an interesting application of the conferencing system, we have developed a telepresenter by which users can remotely attend lectures in progress. We present initial experiences with the system.     

Round‐Robin Tournaments with a Dominant Player

We analyze the subgame perfect equilibrium of the round‐robin tournament with one strong (dominant) and two weak players, and we compare this tournament and the one‐stage contest with respect to the players' expected payoffs, expected total effort, and their probabilities of winning. We find that if the contest designer's goal is to maximize the players' expected total effort, then – if the asymmetry between the players is relatively low – the one‐stage contest should be used. However, if the asymmetry is relatively high, then the round‐robin tournament should be used.     

OPTIONED PORTFOLIO SELECTION: MODELS AND ANALYSIS

The mean‐variance model of Markowitz and many of its extensions have been playing an instrumental role in guiding the practice of portfolio selection. In this paper we study a mean‐variance formulation for the portfolio selection problem involving options. In particular, the portfolio in question contains a stock index and some European style options on the index. A refined mean‐variance methodology is adopted in our approach to formulate this problem as multistage stochastic optimization. It turns out that there are two different solution techniques, both lead to explicit solutions of the problem: one is based on stochastic programming and optimality conditions, and the other one is based on stochastic control and dynamic programming. We introduce both techniques, because their strengths are very different so as to suit different possible extensions and refinements of the basic model. Attention is paid to the structure of the optimal payoff function, which is shown to possess rich properties. Further refinements of the model, such as the request that the payoff should be monotonic with respect to the index, are discussed. Throughout the paper, various numerical examples are used to illustrate the underlying concepts.     

我国循环农业发展模式探究

通过研究,探究构建适合我国循环农业的发展模式。随着经济的快速发展,人类社会生存与可持续发展受到能源危机和环境污染的影响和制约。在全球"低碳经济"的背景之下,我国也在探寻有着中国特色的低碳经济发展模式。而在农业生产领域,传统石油农业的高消耗、高污染已经不能适应当前国家发展的要求,因此,低碳农业、循环农业应运而生。     

On multistage flexible comprehensive evaluation of complicated system

The paper analyzed characters of complicated system and discussed the reason of comprehensive evaluation, realization of flexible comprehensive evaluation was researched from prospect of dynamic measure selection of evaluation, balance of functionality and harmony, uncertainty factor. In the end, multistage flexible comprehensive evaluation of complicated system was applied to performance evaluation of firm.     

多级循环逆流法从柿了树落叶中提取天然熊果酸新工艺

文章介绍了采用多级循环逆流法从柿子树落叶中提取天然熊果酸新工艺的技术原理、主要技术指标及技术创新点,阐述了研制过程中关键技术与工艺及项目鉴定结论。     

一种高频谱纯度的C频段宽带频率合成器设计

为了提高频综的频谱纯度，提出了一种新型多级子谐波混频锁相环的设计方法,研制了一款超低相噪频综。介绍了该频综的设计方案，分析了关键技术，仿真和论证了相位噪声和杂散抑制等主要指标，最后对该频综进行了研制和实际测试。测试结果如下：工作频率为4 500~7 600 MHz，频率步进小于1 kHz，相位噪声优于-123 dBc/Hz@25 kHz，频率切换速度小于75 μs，杂散抑制大于70 dB，均满足设计要求，设计方案比较合理可行。采用该方法设计的频综具有小步进、低相噪、换频速度快、低杂散等特点，可用于高性能电子战接收机中，具有广阔的应用前景。     

多级维纳滤波测向算法的参考信号优化方法

多级维纳滤波（MSWF）利用接收数据矩阵的正交分解,代替了传统MUSIC算法对协方差矩阵 的特征分解,降低了运算量。为有效提高算法性能,对参考信号的取值进行了研究,发现方 向矩阵的取值对其有很大影响。在参考信号取值结构为阵元接收数据的基础上提出参考信号 取值公式,指出了文中条件下参考信号的最优取值。仿真结果表明,在相同条件下该优化方 法比其他算法有更好的性能,对于提高算法精度具有重要意义。