Market Reactions to Zero or Small Positive Sales Surprise

This paper studies how the stock market reacts to zero or small positive sales surprise. Using data from firms listed in the U.S., the paper shows that before 2003 investors react more to positive earnings surprises while after 2003 they react more to the opposite. When sales forecasts are first reported, investors believe in sales numbers and favor firms that meet or beat sales forecasts, but after 2003, investors grow skeptical, realize the possibility of sales management and trust more in negative sales surprises. One thing in common for both two samples is that Sales Response Coefficients of extreme sales surprises are smaller than those of moderate sales surprises

Fuzzy matching: multi-authority attribute searchable encryption without central authority

Attribute-based keyword search (ABKS) supports the access control on the search result based upon fuzzy identity over encrypted data, when the search operation is performed over outsourced encrypted data in cloud. However, almost ABKS schemes trust a single authority to monitor the attribute key for users. In practice, we usually have different entities responsible for monitoring different attribute keys to a user. Thus, it is not realistic to trust a single authority to monitor all attributes keys for ABKS scheme in practical situation. Although a large body of ABKS schemes have been proposed, few works have been done on multi-authority attribute searchable encryption. We propose a multi-authority attribute searchable encryption without central authority in this paper. Comparing previous ABKS schemes, we extend the single-authority ABKS scheme to multi-authority ABKS scheme and remove the central authority in multi-authority ABKS scheme. We analyze our scheme in terms of security and efficiency

Outsourced decentralized multi-authority attribute based signature and its application in IoT

IoT devices often collect data and store the data in the cloud for sharing and further processing. A natural solution for secure access is directly using the device owner?s identity as the private key to generate a signature for data authentication. However this will simultaneously expose this identity. Attribute based signature (ABS), which takes the signer?s attributes instead of his/her identity as the private key, can realize data authentication while preserving the signer?s identity privacy. In ABS, there are multiple authorities that issue different private keys for signers based on their various attributes, and a central authority is usually established to manage all these attribute authorities. However, one security concern is that if the central authority is compromised, the whole system will be broken. In this paper, we present an outsourced decentralized multi-authority attribute based signature (ODMA-ABS) scheme. The proposed ODMAABS achieves attribute privacy and stronger authority-corruption resistance than existing multi-authority attribute based signature schemes. In addition, the overhead to generate a signature is further reduced by outsourcing expensive computation to a signing cloud server. We provide extensive security analysis and experimental simulation of the proposed scheme. We also propose an access control scheme that is based on ODMA-ABS

Confidentiality-preserving publicly verifiable computation schemes for polynomial evaluation and matrix-vector multiplication

With the development of cloud services, outsourcing computation tasks to a commercial cloud server has drawn attention of various communities, especially in the Big Data era. Public verifiability offers a flexible functionality in real circumstance where the cloud service provider (CSP) may be untrusted or some malicious users may slander the CSP on purpose. However, sometimes the computational result is sensitive and is supposed to remain undisclosed in the public verification phase, while existing works on publicly verifiable computation (PVC) fail to achieve this requirement. In this paper, we highlight the property of result confidentiality in publicly verifiable computation and present confidentiality-preserving public verifiable computation (CPPVC) schemes for multivariate polynomial evaluation and matrix-vector multiplication, respectively. The proposed schemes work efficiently under the amortized model and, compared with previous PVC schemes for these computations, achieve confidentiality of computational results, while maintaining the property of public verifiability. The proposed schemes proved to be secure, efficient, and result-confidential. In addition, we provide the algorithms and experimental simulation to show the performance of the proposed schemes, which indicates that our proposal is also acceptable in practice

Analysis of Physical Activity and Sedentary Behavior of Chinese Workers in Different Occupations.

departmental bulletin pape

Cobalt phosphosulfide nanoparticles encapsulated into heteroatom-doped carbon as bifunctional electrocatalyst for Zn−air battery

The design of non‐noble electrocatalysts with low overpotential, high effectiveness, and good cycling stability for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desirable for high-performance Zn–air batteries. Herein, CoPS nanoparticles encapsulated with S, P, N tri-doped carbon material (SPNC) is proposed as bifunctional electrocatalyst of ORR and OER derived from zeolitic imidazolate framework-67. Density functional theory calculations consistently reveal that P element in CoPS@SPNC improve the electrical conductivity and reduce OH* hydrogenation energy barrier on Co sites, thereby facilitating the overall ORR/OER activities. A flexible Zn–air battery with CoPS@SPNC delivers an overpotential of 0.49 V, an energy efficiency above 80%, and a discharge voltage of 1.29 V at 2 mA cm−2 for 80 h. Such strategy could provide numerous possibilities for the design of highly efficient electrocatalysts