信用建设“解忧”共享经济

4月底,支付宝开通了共享单车的服务,ofo、哈罗单车、优拜单车和永安行等5家共享单车公司接入。用支付宝扫一扫共享单车的二维码,可以免押金骑行,到达目的地后锁上单车,进行车费结算。从共享出行的uber、共享空间的airbnb到共享美食的回家吃饭,共享经济逐渐成为社会服务行业的重要组成部分,共享的模式也深刻地影响着我们的生活。所谓共享经济,指是以获取一定报酬为主要目的,基于陌生人且物品使用权暂时转移的一种新的模式。

上海着力构筑大市场体系

去年,上海市新成立国家级要素市场八家,连同前两年成立的上海证券市场和金属交易所,已形成了十大要素市场。 新建成的八大市场,包括石油、煤炭、粮油、汽车、化工、建材、农资、机电八大交易所,它们都是参照上海前年建立的金属交易所经验,不同程度地引进了市场的高级形态——期货交易机制,建立了会员制,保证金制度,采用集中交易,公开竞价和统一结算等先进的现代化制度,会员单位都注意吸收实力雄厚的“国家队”参加,广泛采用国际上先进的交易手段和技术。

Meta-analysis of potentially confounding effect of class size on associations between object-oriented metrics and maintainability

This paper uses three size metrics,which are collectable during the design phase,to analyze the potentially confounding effect of class size on the associations between object-oriented（OO）metrics and maintainability.To draw as many general conclusions as possible,the confounding effect of class size is analyzed on 127 C＋＋ systems and 113 Java systems.For each OO metric,the indirect effect that represents the distortion of the association caused by class size and its variance for individual systems is first computed.Then,a statistical meta-analysis technique is used to compute the average indirect effect over all the systems and to determine if it is significantly different from zero.The experimental results show that the confounding effects of class size on the associations between OO metrics and maintainability generally exist,regardless of whatever size metric is used.Therefore,empirical studies validating OO metrics on maintainability should consider class size as a confounding variable.

走进京城二手电脑市场

随着科技的快速发展,电脑己经变成了人们日常生活工作不可或缺的工具了。但几千元的价格,还是让许多穷朋友望而却步。而且现在电脑的功能已远远超出了部分使用者的要求,许多老旧的电脑依然有着用武之地。另外,许多单位、个人因为升级或其他原因,手头有大最的闲置旧电脑可供出售。即有货源又有需求,于是就出现了很多电脑旧货交易。本期“装机市场”栏目就和大家一起逛一逛这二手电脑市场。

Data Flow&Transaction Mode Classification and An Explorative Estimation on Data Storage&Transaction Volume

The public has shown great interest in the data factor and data transactions,but the current attention is overly focused on personal behavioral data and transactions happening at Data Exchanges.To deliver a complete picture of data flaw and transaction,this paper presents a systematic overview of the flow and transaction of personal,corporate and public data on the basis of data factor classification from various perspectives.By utilizing various sources of information,this paper estimates the volume of data generation&storage and the volume&trend of data market transactions for major economies in the world with the following findings:(i)Data classification is diverse due to a broad variety of applying scenarios,and data transaction and profit distribution are complex due to heterogenous entities,ownerships,information density and other attributes of different data types.(ii)Global data transaction has presented with the characteristics of productization,servitization and platform-based mode.(iii)For major economies,there is a commonly observed disequilibrium between data generation scale and storage scale,which is particularly striking for China.(i^v)The global data market is in a nascent stage of rapid development with a transaction volume of about 100 billion US dollars,and China s data market is even more underdeveloped and only accounts for some 10%of the world total.All sectors of the society should be flly aware of the diversity and complexity of data factor classification and data transactions,as well as the arduous and long-term nature of developing and improving relevant institutional systems.Adapting to such features,efforts should be made to improve data classification,enhance computing infrastructure development,foster professional data transaction and development institutions,and perfect the data governance system.

Designing Trade Rules to Promote Climate Sustainability

Climate sustainability has become a key issue of our time. Measures protecting the environment, however, can have an impact on the competitiveness of domestic firms and on cross-border trade. Therefore, regulatory bodies should enlarge the scope of their policies and treat climate sustainability as global public good; based on such concept trade rules are to be designed in a way that allows a fair balancing between the diverse interests.

Cultural study on trade disputes between China and the West

In recent years, China＇s international trade has made great actuevements, However, when carefully reviewing its performance in the international market, we have to admit a fact that ＂Chinese businessmen＂ and ＂Made in China＂ are encountering great challenges, even aversion in many foreign markets. The so-called ＂Yellow peril theory＂ and ＂China threat theory＂ have caught on once again. Faced with such frequent trade conflicts, we fall into contemplation. Why did trade conflicts so frequently happen？ Do these conflicts merely remain at the commercial level？ Or, are there any deep-seated conflicts leading to trade conflicts？ What are the root causes of these conflicts？ How to overcome and avoid these conflicts in the future？ With these questions, this paper is designed to inquire into the root cause of trade conflicts and the constructive suggestions to settle trade conflicts from a cultural perspective.

Dynamic Portfolio Choice under Uncertainty about Asset Return Model

The effect of uncertainty about stochastic diffusion model on dynamic portfolio choice of an investor who maximizes utility of terminal portfolio wealth was studied.It applied stochastic control method to obtain the closed-form solution of optimal dynamic portfolio,and used the Bayesian rule to estimate the model parameters to do an empirical study on two different samples of Shanghai Exchange Composite Index.Results show,model uncertainty results in positive or negative hedging demand of portfolio,which depends on investor's attitude toward risk;the effect of model uncertainty is more significant with the increasing of investment horizon,the decreasing of investor's risk-aversion degree,and the decreasing of information;predictability of risky asset return increases its allocation in portfolio,at the same time,the effect of model uncertainty also strengthens.

Carbon Emissions in International Trade： Calculating Size and Causes

Due to ongoing growth in carbon emission, many governments＇ have taken measures to curb it. Thus, it is of great importance to measure carbon emissions in international trade and probe into the causes behind them. This paper first applies inputoutput model then it estimates the carbon emissions embodied in China＇s international trade in 2002, 2005 and 2007. Using structural decomposition analysis, this paper measures carbon emissions in international trade by their scale effect, composition effect and intensity effect. Our results illustrate： （1） a rapidly-rising net export of carbon emissions for China, and （2） scale effect and composition effect stimulates carbon emissions embodied in exports, while intensity effect discourages it.

A Multi-Objective Genetic Algorithm for Optimal Portfolio Problems

This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is proposed, and the model is formulated as a non-smooth and nonlinear integer programming problem with multiple objective functions. As it has been proven that finding a feasible solution to the problem only is already NP-hard, based on NSGA-II and genetic algorithm for numerical optimization of constrained problems (Genocop), a multi-objective genetic algorithm (MOGA) is designed to solve the model. Its features comprise integer encoding and corresponding operators, and special treatment of constraints conditions. It is illustrated via a numerical example that the genetic algorithm can efficiently solve portfolio selection models proposed in this paper. This approach offers promise for the portfolio problems in practice.

Addition of Minority Languages to Standards of Safety Information

The necessity of adding safetyinformation which is in minority languagesinto standards is discussed.The requirementsof the WTO-TBT agreement and IECare analyzed.The relevant laws and foundationtechnology for minority languages inChina are discussed.The precedents ofstandards or technical regulations are enumerated.The conclusion is put forward thatsafety information in minority languagesshould be added into standards as soon aspossible.

British Early Intervention in the Slave Trade With Oman 1822-1873

This study tackles the considerable role played by the slave trade in Oman （between 1822-1873）. It also shows the direct relation between this trade and the active role played by the British government in suppressing this trade, which was supported by the law decreed by the British Parliament in 1807. This law declared the abolition of the slave trade considering in illegal in all ports under British jurisdiction and decreed a punishment of exile to all persons involved in this trade. In these circumstances Oman became one of the countries concerned and interested to work and cooperate with the British authorities to end this trade. This was shown in a number of treaties such as the treaty of 1822, 1839, 1845 with the Imam of Oman Sayyid Said bin Sultan and the treaty of 1849 with the Governor of Sohar, Sayyid Saif bin Hamud. These treaties gave the British Government, as represented by its fleet in the Indian Ocean the fight to check, inspect and confiscate any Omani ship found involved in the slave trade. This research also illustrates the role of the Omani government in enforcing these treaties by pursuing and bringing to court all those who were found guilty practicing this trade. One of the main subjects discussed during the period of study is the number of ships involved in this activity, the number of slaved carried by these ships and the legal measures taken against the owners of these ships. Both British and Omanis worked together to find effective ways and means to stop this trade. Finally this study depended on a number of British documents both published and unpublished as well as other European sources.

电子商务网络环境治理的思考

随着以互联网、云计算、物联网等为代表的信息技术的飞跃式发展,电子商务与实体经济开始深度融合,已经成为当前商务领域最前沿、最活跃、最具影响的热点之一。近年来,互联网金融、打车软件等成为了全社会广泛关注的热点。实际上,随着以互联网、云计算、物联网等为代表的信息技术的飞跃式发展,电子商务与实体经济开始深度融合,已经成为当前商务领域最前沿、最活跃、最具影响的热点之一。

江西31个县跻身全国电商500强县

7月28日,我省上半年商务运行数据“出炉”。在国际经济复苏缓慢、国内经济下行压力加大的情况下,我省借力“互联网+”和“一带一路”等发展契机,对外承包工程累计完成营业额增长25.9%,对外直接投资额增长63%,外贸出口明显好于全国。今年,我省商务经济的最大特点,就是“互联网+”风生水起。截至6月底,我省电子商务经营主体突破6.2万家。其中,电商应用企业约6800余家。

Optimal Military Spending,Trade and Stochastic Economic Growth

Based on the procedure of dynamic programming,this paper investigates the military spending,trade and wealth accumulation in a stochastic endogenous economic growth model.For the Cobb-Dauglas utility function,explicit solutions of the optimal problem of the home country are obtained.Meanwhile,the optimal consumptions of domestic goods and foreign goods,the share of domestic capital stock and foreign bond holdings are derived explicitly.The comparative dynamic analysis shows that when intertemporal substitution in consumption is relative elastic,economic growth has a positive correlation with foreign military spending,has a negative correlation with variance of foreign military spending,and has a positive correlation with variance of capital or bonds if capital and bonds yields the same benefits.However,in the case of inelasticity,variance of foreign military spending may stimulate or weaken economic development.

ROBUST TRADING RULE SELECTION AND FORECASTING ACCURACY

Trading rules performing well on a given data set seldom lead to promising out-of-sample results, a problem which is a consequence of the in-sample data snooping bias. Efforts to justify the selection of trading rules by assessing the out-of-sample performance will not really remedy this predica- ment either, because they are prone to be trapped in what is known as the out-of-sample data-snooping bias. Our approach to curb the data-snooping bias consists of constructing a framework for trading rule selection using a-priori robustness strategies, where robustness is gauged on the basis of time- series bootstrap and multi-objective criteria. This approach focuses thus on building robustness into the process of trading rule selection at an early stage, rather than on an ex-post assessment of trading rule fitness. Intra-day FX market data constitute the empirical basis of the proposed investigations. Trading rules are selected from a wide universe created by evolutionary computation tools. The authors show evidence of the benefit of this approach in terms of indirect forecasting accuracy when investing in FX markets.

Scale Effects of Geographical Soil Datasets on Soil Carbon Estimation in Louisiana,USA:A Comparison of STATSGO and SSURGO

Estimation of soil organic carbon （SOC） pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database （SSURGO）, currently the most detailed level with a map scale ranging from 1：12 000 to 1：63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1） compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database （STATSGO）, and referenced field measurements at the soil map unit; 2） examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3） quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4） assess scale effects on soil organic carbon density （SOCD） estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter （SOM） content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit （R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth： 30 cm）. However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth （up to 2.75 m） soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.

STOCHASTIC PROGRAMMING METHOD FOR MULTIPERIOD CONSUMPTION AND INVESTMENT PROBLEMS WITH TRANSACTIONS COSTS

Using the GARCH model to describe the risky asset's return process so thatits time-varying moments and conditional heteroskedasticity can be properly reflected,general multiperiod optimal investment and consumption problems with both fixed andproportional transactions costs are investigated in this paper. We model this kind ofdifficult problems as a dynamic stochastic optimization problem, which can cope withdifferent utility functions and any number of time periods. The procedure to solve theresulting complex nonlinear stochastic optimization problem is discussed in detail and abranch-decomposition algorithm is devised.

An Optimal Portfolio Model with Transaction Cost

In this paper, a convex programming model for portfolio select with trans- action costs was present, we proved the existence condition of optimal solution, and gave a simple example to the optimal solution.

Industrial structure optimization in central China under the energy constraint

Optimizing industrial structure is an important research object of human-economic geography, and it is also the object of government departments to strengthen macro-control. This has become even greater problem that China has entered the "new normal" in recent years. The study uses a multi-regional input-output model, with linear programming to build an optimal model of industrial structure as well as a model of optimization degree under the energy constraint. The results of the study revealed that:(1) the degree of optimization of industrial structure in Anhui Province is optimal(0.763), while that of Shanxi Province is the lowest(0.662);(2) the degree of optimization of industrial structure is negatively related to energy consumption per unit output value and the proportion of heavy industry; and(3) overall, central China should maintain or moderately increase the proportions of resource-based industry, greatly increase the proportions of manufacturing, including transport and telecommunications equipment, computers and other electronic equipment, and moderately reduce the proportions of smelting and pressing of metals and non-metal mineral products. In terms of service industries, the region should greatly increase the proportions of the production and supply of natural gas and tap water, moderately reduce or maintain the proportions of transport and storage as well as tourism, and maintain or moderately reduce the proportions of wholesale trade, retail trade and catering services.