Modeling Reputation Management System on Online C2C Market

This paper discusses the effectiveness of sharing information concerning the reputations of buyers and sellers making online transactions in a consumer-to-consumer (C2C) market. We developed a computer simulation model that describes online transactions with a reputation management system that shares information concerning the reputations of consumers. The model takes an agent-based approach in which agents' actions are based on the iterated prisoner's dilemma. No model exists to analyze C2C markets even though there are many case studies concerning the effectiveness of sharing reputation information among participants in a market. The simulation results revealed that a positive reputation system can be more effective than a negative reputation system for an online transaction, even though the negative one can work for a traditional transaction. The result should be an important consideration when designing practical reputation management systems for online transactions.     

Vertically differentiated duopoly with unaware consumers

We study information disclosure in a vertically differentiated duopoly with unaware consumers. Sellers have private information about the adverse effect of their products, while consumers are unaware of existence of such adverse effect unless they are informed by the sellers. We show that information remains hidden only if information disclosure reduces the size of the market. In such a case, whether information is disclosed depends on the intensity of competition, the difference of the adverse effect between the two sellers, and the timing at which pricing and information disclosure decisions are made.     

Optimal control of a quality supervision profit model for the electronic intermediary

Online customers execute transactions without inspecting products could expect to encounter risks of receiving products with unsatisfactory qualities, especially in food transactions. Thus quality supervision plays a key role in the establishment of trust as well as in the management of risk between online customers and sellers. Most papers in this field are in qualitative nature. In this paper, a quality supervision profit(QSP) model is formulated as a discrete-time optimal control problem. It is a quantitative approach, and it broadens the scope of current research in the area. The quality effort level of online sellers(QELs) and the quality supervision level of the electronic intermediary(QSLm) are considered together with their corresponding profit in the proposed model. The aim is to optimize an overall profit. A case study arising from Suichang's food traceability system(FTS) of farm produce online transaction is carried out in details. The results reveal that QELs, QSLm and the profit distribution coefficient have a strong influence upon the profits of both sides. Finally, some concluding remarks,including potential further research topics, are given.     

C2C模式下卖家信誉建立与提升策略研究

当前信誉已成为电子商务发展中不可回避的问题.C2C模式下,信誉是交易进行的基础,它直接关系着交易的安全有效.从卖家收益的视角出发,运用博弈理论分析了C2C模式下卖家信誉的演化过程,提出了惩罚和信任两种策略的适用条件.结果表明对于新进入的卖家,发表承诺和买方的惩罚能够促使其建立信誉,而对于已具有一定信誉值的卖家而言,买家的充分的信任和积极评价将是其维持和提升信誉的动力来源.     

流动性能提高套利交易的盈利吗？——基于中国股市的证据

本文以新兴市场重要组成部分之一的中国股市为例,对市场总体流动性水平与套利交易盈利能力间的关系进行了深入分析。与成熟资本市场中的状况相反,本文研究发现,在控制了Fama-French三因子后,套利交易的预期盈利随着市场流动性水平的提高而增加,表明市场异象造成的错误定价并不会随着流动性的提高而被投资者的套利交易所纠正,这体现了不成熟市场的特征,且反映了套利的无效率。另外,本文在分析中还考虑了流动性风险和时变因素风险暴露等可能对研究结论造成影响的因素,并且在进一步研究后得到了与前文相一致的结论。     

An adaptive evaluation mechanism for online traders

Economic agents in electronic markets generally consider reputation to be a significant factor in selecting trading partners. Most traditional online businesses publish reputation profile for traders that reflect average of the ratings received in previous transactions. Because of the importance of these ratings, there is an incentive for traders to partake in strategic behavior (for example shilling) to artificially inflate their rating. It is therefore important for an online business to be able to provide a robust estimate of a trader’s reputation that is not easily affected by strategic behavior or noisy ratings. This paper proposes such an adaptive ratings-based reputation model. The model is based on a trader’s transaction history, witness testimony, and other weighting factors. Learning is integrated to make the ratings model adaptive and robust in a dynamic environment. To validate the proposed model and to demonstrate the significance of its constructs, a multi-agent system is built to simulate the interactions among buyers and sellers in an electronic marketplace. The performance of the proposed model is compared to that of the reputation model used in most online marketplaces like Amazon, and to Huynh’s model proposed in the literature.     

Multifractal structure in Latin-American market indices

We study the multifractal nature of daily price and volatility returns of Latin-American stock markets employing the multifractal detrended fluctuation analysis. Comparing with the results obtained for a developed country (US) we conclude that the multifractality degree is higher for emerging markets. Moreover, we propose a stock market inefficiency ranking by considering the multifractality degree as a measure of inefficiency. Finally, we analyze the sources of multifractality quantifying the contributions of two factors, the long-range correlations of the time series and the broad fat-tail distributions. We find that the multifractal structure of Latin-American market indices can be mainly attributed to the latter.     

A Continuous Time Financial Market with a Poisson Process as Transaction Timer

We study the influence of transactions on investors' portfolio values under the assumption that the investors' transaction times are determined by Poisson point processes, whose intensity measures can naturally be interpreted as transaction frequencies. We give lower and upper bounds on the expectations of portfolio values in terms of transaction intensities, and prove that there exist a sequence of portfolio fractions and a transaction frequency which maximize the expectation of the portfolio value for a finite horizon. We also give bounds on transaction frequencies for preventing the investors from losing money. Then the optimal transaction strategies for finite and infinite time horizons and the asymptotic effects of making transactions are discussed based on the concept of a benefit function of transactions. Finally, we investigate the influence of transactions on financial markets, with the market mean rates of return and volatilities being connected with the transaction frequency. We show that the market becomes unprofitable in a finite time if an overwhelming amount of transactions is involved and the market is suitable for some limited transactions when its trade capacity does not increase beyond any limit at a relatively high speed. Our models and simulations illustrate how the investors' collective action affects the financial market.     

存在水平差异化的多寡头双边平台企业竞争研究

构建了多寡头双边平台企业竞争的Salop双环模型,研究了双边平台企业在不同规模下均衡解的存在性以及均衡解的结构。研究发现:不论双边平台企业规模如何,双边平台企业的收益不仅受平台对买卖双方制定的价格总量的影响,而且还受价格结构的影响;多寡头双边平台企业在竞争中存在明显的买方市场时,买方并不能获得类似单边市场里的主动权,且若卖方存在竞争,则无论买方是否存在竞争,均不存在均衡解;无论是买方竞争还是卖方竞争,若存在均衡解,则对双边平台企业、买方和卖方均有利,出现三方多赢的局面。     

信息不对称条件下竞价排名机制的信息匹配效率研究

本文聚焦消费者依赖搜索引擎平台的关键词检索实施购买商品行为的现象,尝试将消费者购买策略引入搜索平台竞价排名机制,构造内嵌搜索引擎平台、销售商、消费者三方主体的博弈模型,考察在互联网信息不对称条件下,竞价排名机制的信息匹配效率,阐释产品质量信号改善竞价排名机制信息匹配效率的理论机理。研究发现,在信息不对称及无产品质量信号机制的条件下,竞价排名均衡结果完全不能匹配消费者的购买策略,致使消费者福利因销售商逆向选择而遭受双重损失;植入产品质量信号后,搜索引擎平台能够通过识别销售商自带的产品质量信号,提高竞价排名机制的均衡结果与消费者购买策略的匹配度,进而部分地改善竞价排名机制的信息匹配效率。     

A Note on the Suboptimality of Path-Dependent Pay-Offs in Lévy Markets

Abstract

Cox and Leland used techniques from the field of stochastic control theory to show that, in the particular case of a Brownian motion for the asset log-returns, risk-averse decision makers with a fixed investment horizon prefer path-independent pay-offs over path-dependent pay-offs. In this note we provide a novel and simple proof for the Cox and Leland result and we will extend it to general Lévy markets where pricing is based on the Esscher transform (exponential tilting). It is also shown that, in these markets, optimal path-independent pay-offs are increasing with the underlying final asset value. We provide examples that allow explicit verification of our theoretical findings and also show that the inefficiency cost of path-dependent pay-offs can be significant. Our results indicate that path-dependent investment pay-offs, the use of which is widespread in financial markets, do not offer good value from the investor's point of view.     

Analysis of the core of multisided Böhm-Bawerk assignment markets

We introduce the class of multisided Böhm-Bawerk assignment games which generalizes the well-known two-sided Böhm-Bawerk assignment games to markets with an arbitrary number of sectors. We reach the core and the corresponding extreme allocations of any multisided Böhm-Bawerk assignment game by means of an associated convex game defined on the set of sectors instead of the set of sellers and buyers. We also study when the core of a multisided Böhm-Bawerk assignment game is stable in the sense of von Neumann–Morgenstern.     

不透明销售的顾客退货政策选择

本文探讨从事不透明销售的零售商对顾客退货政策的选择问题。分别针对零售商垄断和竞争两种市场情况,建立不透明零售商与其它供应链成员(制造商或普通零售商)之间的博弈模型,获得唯一均衡解;对均衡结果进行结构化分析,给出不透明销售方式下采用全额退款政策的判别条件;针对均衡结果,分析零售商垄断情况下产品不透明参数的最优设计,以及零售商竞争情况下的市场分化情况;鉴于净残值参数在退货政策选择中的决定性作用,本文进一步探讨了净残值为正时全额退款政策对各参与方利润及产品需求和价格的影响,分析了净残值在其中的作用机理。本研究能够为不透明零售商制定退货政策和价格以及其它供应链成员制定相关决策提供支持。     

Firm and industry level profit efficiency analysis using absolute and uniform shadow prices

We discuss the nonparametric approach to profit efficiency analysis at the firm and industry levels in the absence of complete price information. Two new insights are developed. First, we measure profit inefficiency in monetary terms using absolute shadow prices. Second, we evaluate all firms using the same input–output prices. This allows us to aggregate firm-level profit inefficiencies to the overall industry inefficiency. Besides the measurement of profit losses, the presented approach enables one to recover absolute price information from quantity data. We conduct a series of Monte Carlo simulations to study the performance of the proposed approach in controlled production environments.     

An efficiency comparison of the non-life insurance industry in the BRIC countries

We analyze the efficiency of non-life insurance companies in four of the fastest-growing markets in the world—the BRIC (Brazil, Russia, India, China) countries. An innovative feature of this paper is its incorporation of uncontrollable variables in the efficiency analysis using multi-stage data envelopment analysis (DEA). This approach captures cross-country differences, such as the political and economic environment, and allows distinguishing between managerial inefficiency and inefficiency due to environmental conditions. We find that the environment affects the efficiency of non-life insurers operating in the BRIC countries. Furthermore, in a regression of firm characteristics on efficiency scores we identify four drives of efficiency: Size, profitability, solvency, and ownership form. The results further our understanding of the insurance industry in the BRIC countries in regard to its efficiency and the environment in which it operates.     

A double-sided multiunit combinatorial auction for substitutes: Theory and algorithms

Combinatorial exchanges have existed for a long time in securities markets. In these auctions buyers and sellers can place orders on combinations, or bundles of different securities. These orders are conjunctive: they are matched only if the full bundle is available. On business-to-business (B2B) exchanges, buyers have the choice to receive the same product with different attributes; for instance the same product can be produced by different sellers. A buyer indicates his preference by submitting a disjunctive order, where he specifies the quantity he wants of each particular good and what limit price he is willing to pay for each good, thus providing a subjective valuation of each attribute. Only the goods with the best prices will be traded. This article considers a doubled-sided multiunit combinatorial auction for substitutes, that is, a uniform price auction where buyers and sellers place both types of orders, conjunctive (AND orders) and disjunctive (XOR orders). We show that linear competitive prices exist. We also propose an algorithm to clear the market, which is particularly efficient when the number of traders is large, and the goods are divisible.     

A decision approach to competitive electronic sealed-bid auctions for land

Electronic markets for land are innovative techniques potentially advantageous to buyers and private sellers, the latter being interested in sealed-bid auctions assuring high levels of competition among many bidders so that coalitions and cooperative games are ruled out. Land electronic tendering requires sufficient online information for bidders such as valuation reports by prestigious surveyors. To help the bidder make his best choice, we propose a decision model for moderately pessimistic players facing tenders where competition among a great number of independent antagonists excludes the use of cooperative games and involves strict uncertainty. A worked example concerning farmland in Spain is presented.     

Real Estate Appraisal: A Double Perspective Data Envelopment Analysis Approach

This paper proposes a new methodology for the assessment of the value range for real estate units. The theoretical basis of the methodology is built on the Data Envelopment Analysis—DEA approach, which has its original concept adapted to the case where the units under assessment consist of transactions among sellers and buyers. The proposed approach—christened Double Perspective-Data Envelopment Analysis (DP-DEA)—is applied to a database comprising the prices and features of the units under assessment. It is shown that the DP-DEA presents some specific advantages when compared to the usual regression analysis method employed in real estate value assessment.     

信息技术投入对市场均衡的影响及厂商策略分析

主要利用Hotelling模型分析厂商采取信息技术降低生产成本时对于市场均衡的影响,证明了信息技术投入多、具有信息技术优势的厂商的厂商与信息技术投入少、信息技术劣势的厂商相比,前者拥有更低的成本与价格,以及更高的市场份额与利润.并且随着信息技术对于降低成本的贡献率的不断增大,信息技术优势厂商所获得的利润也不断增多.回答了当存在信息技术水平不同时,厂商相应的策略选择问题.     

The quality guaranteeing price with market anonymity

When the information of buyers and sellers regarding the quality of a good is asymmetric, the threat of terminating a cheating seller can assure performance (Klein and Leffler [1981], Telser [1980]). However, except in very small markets, this threat is impossible to implement. The reason is that beyond a certain market size anonymity sets in: The personal identities of agents are no longer always known. Thus, although cheating firms could still be terminated, their owners could not. The most severe threat that is available to the buyer when there is anonymity is to terminate the cheating firm. But because a cheating owner could either reenter the same industry (by starting a new firm), or enter another industry that offered similar rents, the effectiveness of this threat depends on the size of the market: In a large market the probability that a new firm will get buyers is small, and with a sufficiently high price not cheating would be more profitable than cheating and trying ro reenter. In a market of only a medium size, however, the probability of successful reentry may be so high that cheating would dominate not cheating for any price that is below the buyers' reservation price. For markets with asymmetric information market size is, therefore, of crucial importance, and this is the first question that this paper deals with. The model that the paper develops determines both the minimal market size that is necessary to prevent market failure, and the actual market size that will endogenously emerge. If entry costs were very high, however, not cheating would dominate cheating regardless of the size of the market. Could “artificial” entry costs be created in order to deter cheating when there is anonymity? This is the second issue that the paper will address.