the present study considered the situation of kilka stocks in last decades by using overfished biomass threshold, fishing effort ratio and fishing mortality proxy during 1991-2010. the cpue index of anchovy and mixed-species of kilka indicated an undepleted from 1991 to 2000. in 2000, the cpue ratio declined to close to the “in danger” region, and subsequently collapsed to “overfished” region f...

Proxy reconstructions from the mid-Holocene (MH: 6,000 years ago) indicate an intensification of West African Monsoon and a weakening South American Monsoon, primarily resulting orbitally-driven insolation changes. However, model studies that account for MH orbital configurations greenhouse gas concentrations can only partially reproduce these Most do not remarkable vegetation changes occurred ...

Proxy signature schemes can be used in many business applications such as when the original signer is not present to sign important documents. Any proxy signature scheme has to meet the identifiability, undeniability, verifiability and unforgeability security requirements. In some conditions, it may be necessary to protect the proxy signer’s privacy from outsiders or third parties. Recently, se...

Delegation of rights is a common practice in the real world. We present two identitybased threshold proxy signature schemes, which allow an original signer to delegate her signing capability to a group of n proxy signers, and it requires a consensus of t or more proxy signers in order to generate a valid signature. In addition to identity-based scheme, privacy protection for proxy singers and s...

Proxy signature helps the proxy signer to sign messages on behalf of the original signer. It is very useful when the original signer (e.g. the president of a company) is not available to sign a specific document. If the original signer can not forge valid proxy signatures through impersonating the proxy signer, it will be robust in a virtual environment; thus the original signer can not shift a...

Multi-proxy signature allows an original signer authorizing a proxy group as his proxy agent and only the cooperation of all proxy signers in the group can create a proxy signature on behalf of the original signer. Recently, Jin and Wen defined a formal model of certificateless multi-proxy signature and proposed a concrete scheme. They claimed that their scheme is provably secure in their secur...

This paper proposes an improved RSA-based threshold proxy signature scheme. The proposed scheme satisfies the necessary security requirements of proxy signature such as verifiability, unforgeability, threshold property and identifiability. The proposed scheme does not require any secure channel to deliver the proxy keys any more. Introduction A proxy signature scheme involves three entities: an...

A substantial portion of web traffic consists of queries to database web servers. Unfortunately, a common technique to improve web scalability, proxy caching, is ineffective for database web servers because existing web proxy servers cannot cache queries. To address this problem, we modify a recently proposed enhanced proxy server, called an active proxy, to enable Active Query Caching. Our app...

A (t, n) threshold proxy signature scheme enables an original signer to delegate the signature authority to a proxy group of n member such that t or more than t proxy signers can cooperatively sign messages on behalf of the original signer. In the paper, we review the security of two nonrepudiable threshold proxy signature schemes. We show that Tzeng et al.’s threshold proxy signature scheme is...