Randomized Binomial Tree and Pricing of American-Style Options

Randomized binomial tree and methods for pricing American options were studied. Firstly, both the completeness and the no-arbitrage conditions in the randomized binomial tree market were proved. Secondly, the description of the node was given, and the cubic polynomial relationship between the number of nodes and the time steps was also obtained. Then, the characteristics of paths and storage structure of the randomized binomial tree were depicted. Then, the procedure and method for pricing American-style options were given in a random binomial tree market. Finally, a numerical example pricing the American option was illustrated, and the sensitivity analysis of parameter was carried out. The results show that the impact of the occurrence probability of the random binomial tree environment on American option prices is very significant. With the traditional complete market characteristics of random binary and a stronger ability to describe, at the same time, maintaining a computational feasibility, randomized binomial tree is a kind of promising method for pricing financial derivatives

Secure Mobile Agents in Electronic Commerce by Using Undetachable Signatures from Pairings

It is expect that mobile agents technology will bring significant benefits to electronic commerce. But security issues, especially threats from malicious hosts, become a great obstacle of widespread deployment of applications in electronic commerce based on mobile agents technology. Undetachable digital signature is a category of digital signatures to secure mobile agents against malicious hosts. An undetachable signature scheme by using encrypted functions from bilinear pairings was proposed in this paper. The security of this scheme base on the computational intractability of discrete logarithm problem and computational Diffe-Hellman problem on gap Diffle-Hellman group. Furthermore, the scheme satisfies all the requirements of a strong non-designated proxy signature i.e. verifiability, strong unforgeability, strong identifiability, strong undeniability and preventions of misuse. An undetachable threshold signature scheme that enable the customer to provide n mobile agents with ‘shares’ of the undetachable signature function is also provided. It is able to provide more reliability than classical undetachable signatures

Coordinate-free formation control of multi-agent systems using rooted graphs

This paper studies how to control large formations of autonomous agents in the plane, assuming that each agent is able to sense relative positions of its neighboring agents with respect to its own local coordinate system. We tackle the problem by adopting two types of controllers. First, we use the classical gradient-based controllers on three leader agents to meet their distance constraints. Second, we develop other type of controllers for follower agents: utilizing the properties of rooted graphs, one is able to design linear controllers incorporating relative positions between the follower agents and their neighbors, to stabilize the overall large formations. The advantages of the proposed method are fourfold: (i) fewer constraints on neighboring relationship graphs; (ii) simplicity of linear controllers for follower agents; (iii) global convergence of the overall formations; (iv) implementation in local coordinate systems, in no need of a global coordinate system. Numerical simulations show the effectiveness of the proposed method

Online Social Networks, Media Supervision and Investment Efficiency:An Empirical Examination of Chinese Listed Firms

Prior literature suggests that media reports acting as external supervision improve information transparency and corporate governance leading to increased investment efficiency. This study empirically tests this hypothesis in the context of online social networks by investigating the combined effects of online social networking and media reports on investment efficiency using a sample of Chinese listed firms. Our results show that the interaction of media reports and Tobin's q ratio is negatively related to corporate investment efficiency. However, the introduction of online social networks turns this relationship from a negative to a positive and statistically significant one. The combined factors significantly increase investment efficiency in non-SOEs (State Owned Enterprises) but not in SOEs. We provide evidence that online social networking effectively mitigates the negative effect of media supervision on investment efficiency, further advancing knowledge of the link of external supervision and corporate governance.National Natural Science Foundation of Chin

What Makes it Difficult to Understand a Scientific Literature?

In the artificial intelligence area, one of the ultimate goals is to make computers understand human language and offer assistance. In order to achieve this ideal, researchers of computer science have put forward a lot of models and algorithms attempting at enabling the machine to analyze and process human natural language on different levels of semantics. Although recent progress in this field offers much hope, we still have to ask whether current research can provide assistance that people really desire in reading and comprehension. To this end, we conducted a reading comprehension test on two scientific papers which are written in different styles. We use the semantic link models to analyze the understanding obstacles that people will face in the process of reading and figure out what makes it difficult for human to understand a scientific literature. Through such analysis, we summarized some characteristics and problems which are reflected by people with different levels of knowledge on the comprehension of difficult science and technology literature, which can be modeled in semantic link network. We believe that these characteristics and problems will help us re-examine the existing machine models and are helpful in the designing of new one.Comment: Accepted by SKG201

Structure symmetry determination and magnetic evolution in Sr2Ir1−xRhxO4\rm Sr_2Ir_{1-x}Rh_{x}O_4

We use single-crystal neutron diffraction to determine the crystal structure symmetry and the magnetic evolution in the rhodium doped iridates $\rm Sr_2Ir_{1-x}Rh_{x}O_4$ ($0\leq x \leq 0.16$). Throughout this doping range, the crystal structure retains a tetragonal symmetry (space group $I4_1/a$) with two distinct magnetic Ir sites in the unit cell forming staggered $\rm IrO_6$ rotation. Upon Rh doping, the magnetic order is suppressed and the magnetic moment of Ir$^{4+}$ is reduced from 0.21 $\rm \mu_B$/Ir for $x=0$ to 0.18 $\rm \mu_B$/Ir for $x=0.12$. The magnetic structure at $x=0.12$ is different from that of the parent compound while the moments remain in the basal plane.Comment: Accepted for publication in Phys. Rev.

Simultaneous Metal-Insulator and Antiferromagnetic Transitions in Orthorhombic Perovskite Iridate Sr0.94Ir0.78O2.68 Single Crystals

The orthorhombic perovskite SrIrO3 is a semimetal, an intriguing exception in iridates where the strong spin-orbit interaction coupled with electron correlations tends to impose a novel insulating state. We report results of our investigation of bulk single-crystal Sr0.94Ir0.78O2.68 or Ir-deficient, orthorhombic perovskite SrIrO3. It retains the same crystal structure as stoichiometric SrIrO3 but exhibits a sharp, simultaneous antiferromagnetic (AFM) and metal-insulator (MI) transition at 185 K. Above it, the basal-plane resistivity features an extended regime of almost linear-temperature dependence up to 800 K but the strong electronic anisotropy renders an insulating behavior in the out-of-plane resistivity. The Hall resistivity undergoes an abrupt sign change and grows below 40 K, which along with the Sommerfeld constant of 20 mJ/mole K2 suggests a multiband effect. All results including our first-principles calculations underscore a delicacy of the metallic state in SrIrO3 that is in close proximity to an AFM insulating state. The contrasting ground states in isostructural Sr0.94Ir0.78O2.68 and SrIrO3 illustrate a critical role of even slight lattice distortions in rebalancing the ground state in the iridates. Finally, the observed simultaneous AFM and MI transitions reveal a direct correlation between the magnetic transition and formation of a charge gap in the iridate, which is conspicuously absent in Sr2IrO4.Comment: 5 figure