Centralized Coded Caching with User Cooperation

In this paper, we consider the coded-caching broadcast network with user cooperation, where a server connects with multiple users and the users can cooperate with each other through a cooperation network. We propose a centralized coded caching scheme based on a new deterministic placement strategy and a parallel delivery strategy. It is shown that the new scheme optimally allocate the communication loads on the server and users, obtaining cooperation gain and parallel gain that greatly reduces the transmission delay. Furthermore, we show that the number of users who parallelly send information should decrease when the users' caching size increases. In other words, letting more users parallelly send information could be harmful. Finally, we derive a constant multiplicative gap between the lower bound and upper bound on the transmission delay, which proves that our scheme is order optimal.Comment: 9 pages, submitted to ITW201

Risk and Return of Blockchain Announcements in Chinese Stock Market – An Event Study

Prior research has demonstrated that blockchain announcements are associated with significant stock market reactions on the day of the announcement. However, it is unclear what factors may influence the positive market reaction at the firm level. Moreover, it is unclear whether national policies will affect positive market reactions. Using an event study methodology, we examine investors’ reactions to blockchain announcements issued by Chinese listed companies, taking organizational factors and national policies into account. Results indicate that the stock market reacts positively to blockchain announcements in the IT sector on the day of the announcement. However, there are no significant differences between manufacturing companies and other companies regarding abnormal stock returns. In addition, a CIO (or CTO) and a high percentage of executives with a background in R&D will enhance the positive stock market reaction. Furthermore, we demonstrate that national policies play a significant role in influencing positive stock market reactions

Informed seller problem : signaling, information design, and mechanism design

University of Technology Sydney. Faculty of Business.This thesis studies an informed seller problem in which the seller tries to signal her private information through different channels—information disclosure, selling mechanism and return policy. Chapter 1 analyzes the signalling effect of information disclosure and price posting. Any separating equilibria must have the two types of seller setting different disclosure rules as well as different prices. Furthermore, the outcome that survives the intuitive criterion always exists and is unique. This equilibrium outcome is separating, for which a closed-form solution is provided. The signaling concern forces the high-type seller to disclose an inefficient amount of information and charge a higher price, resulting in fewer sales and lower profit. A regulation on minimal quality could potentially damage social welfare. In chapter 2, the seller is allowed to design a grand mechanism in which she herself participates in addition to information disclosure. The RSW (Rothschild-Stiglitz-Wilson) mechanism is fully characterized, in which each type of seller separates at the lowest cost. In this mechanism, the low-type seller sells to the buyer with certainty and leaves zero surplus to the buyer. The high-type seller discloses to the buyer whether his value is above a cutoff, sets a payment difference equal to the conditional expected value, and provides a nonnegative bonus. Furthermore, the RSW mechanism can always be supported as a PBE and its outcome is the unique PBE outcome under certain conditions. Finally, the RSW mechanism always survives the Intuitive criterion, and is the unique one under certain conditions. Chapter 3 studies an second-price auction with return policies. It starts with binary type. In the separating equilibria, the high-type seller’s return policy needs to be generous enough to deter the low-type seller from mimicking. Notably, a better return policy may not correspond to a better type. In the pooling equilibria, the return policy cannot be too generous. All separating equilibria have the same outcome and all survive Eso and Schummer’s credible deviation criterion while all pooling equilibria fail. Separation is costless and efficient. Similar results apply when sellers have multiple types