Practical Certificateless Aggregate Signatures From Bilinear Maps

Aggregate signature is a digital signature with a striking property that anyone can aggregate n individual signatures on n different messages which are signed by n distinct signers, into a single compact signature to reduce computational and storage costs. In this work, two practical certificateless aggregate signature schemes are proposed from bilinear maps. The first scheme CAS-1 reduces the costs of communication and signer-side computation but trades off the storage, while CAS-2 minimizes the storage but sacrifices the communication costs. One can choose either of the schemes by consideration of the application requirement. Compare with ID-based schemes, our schemes do not entail public key certificates as well and achieve the trust level 3, which imply the frauds of the authority are detectable. Both of the schemes are proven secure in the random oracle model by assuming the intractability of the computational Diffie-Hellman problem over the groups with bilinear maps, where the forking lemma technique is avoided

Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations and β\beta-decay half-lives

The self-consistent quasiparticle random-phase approximation (QRPA) approach is formulated in the canonical single-nucleon basis of the relativistic Hatree-Fock-Bogoliubov (RHFB) theory. This approach is applied to study the isobaric analog states (IAS) and Gamov-Teller resonances (GTR) by taking Sn isotopes as examples. It is found that self-consistent treatment of the particle-particle residual interaction is essential to concentrate the IAS in a single peak for open-shell nuclei and the Coulomb exchange term is very important to predict the IAS energies. For the GTR, the isovector pairing can increase the calculated GTR energy, while the isoscalar pairing has an important influence on the low-lying tail of the GT transition. Furthermore, the QRPA approach is employed to predict nuclear $\beta$-decay half-lives. With an isospin-dependent pairing interaction in the isoscalar channel, the RHFB+QRPA approach almost completely reproduces the experimental $\beta$-decay half-lives for nuclei up to the Sn isotopes with half-lives smaller than one second. Large discrepancies are found for the Ni, Zn, and Ge isotopes with neutron number smaller than $50$, as well as the Sn isotopes with neutron number smaller than $82$. The potential reasons for these discrepancies are discussed in detail.Comment: 34 pages, 14 figure

Quantum Transport Simulation of III-V TFETs with Reduced-Order K.P Method

III-V tunneling field-effect transistors (TFETs) offer great potentials in future low-power electronics application due to their steep subthreshold slope and large "on" current. Their 3D quantum transport study using non-equilibrium Green's function method is computationally very intensive, in particular when combined with multiband approaches such as the eight-band K.P method. To reduce the numerical cost, an efficient reduced-order method is developed in this article and applied to study homojunction InAs and heterojunction GaSb-InAs nanowire TFETs. Device performances are obtained for various channel widths, channel lengths, crystal orientations, doping densities, source pocket lengths, and strain conditions

Independent Visions of Marginal America: Reimagining a Nation Through Outsiders, Searching, and Non-Arrival

This thesis explores critical responses to American-ness, American identity, and most significantly American myth, in independent films about America in cultural terms, and their attempts to deconstruct the myths of nation and culture. The independent films about America analyzed in this thesis range from the 1960s to the 1990s, made by filmmakers across movements and cultures, but they all contain in some measure three key concepts: the “outsider,” the “search,” and a narrative “non-arrival.” Easy Rider (1969) will be explored as the prototype for this paradigm, contrasted with films that reinterpret the road-movie structure away from existential angst and toward richer ambiguities: Alambrista! (1977), Gummo, Stroszek, Chan is Missing, and The Watermelon Woman (1996). Transnationality reflects in the content and production of many “outsider” films; therefore my study replaces the category American films with films in and about America. These films about America are threaded together by the outsider as a position relative to social acceptance and unified identity (the “inside”), and the search as a yearning, a desire for peace, happiness, meaning, etc. molded by transience and instability. The search never yields the result or object the characters intend to find, and within this non-arrival the denial of resolution informs us about the unsurety of life for the outsider, and the elusiveness of the nation as a mythic construct. The unsettling of myth is interpreted as a kind of hauntology, as the ‘haunting’ or persistence of violence and myth is analyzed