Achieving Secrecy Capacity of the Gaussian Wiretap Channel with Polar Lattices

In this work, an explicit wiretap coding scheme based on polar lattices is proposed to achieve the secrecy capacity of the additive white Gaussian noise (AWGN) wiretap channel. Firstly, polar lattices are used to construct secrecy-good lattices for the mod-$\Lambda_s$ Gaussian wiretap channel. Then we propose an explicit shaping scheme to remove this mod-$\Lambda_s$ front end and extend polar lattices to the genuine Gaussian wiretap channel. The shaping technique is based on the lattice Gaussian distribution, which leads to a binary asymmetric channel at each level for the multilevel lattice codes. By employing the asymmetric polar coding technique, we construct an AWGN-good lattice and a secrecy-good lattice with optimal shaping simultaneously. As a result, the encoding complexity for the sender and the decoding complexity for the legitimate receiver are both O(N logN log(logN)). The proposed scheme is proven to be semantically secure.Comment: Submitted to IEEE Trans. Information Theory, revised. This is the authors' own version of the pape

Construction of Capacity-Achieving Lattice Codes: Polar Lattices

In this paper, we propose a new class of lattices constructed from polar codes, namely polar lattices, to achieve the capacity \frac{1}{2}\log(1+\SNR) of the additive white Gaussian-noise (AWGN) channel. Our construction follows the multilevel approach of Forney \textit{et al.}, where we construct a capacity-achieving polar code on each level. The component polar codes are shown to be naturally nested, thereby fulfilling the requirement of the multilevel lattice construction. We prove that polar lattices are \emph{AWGN-good}. Furthermore, using the technique of source polarization, we propose discrete Gaussian shaping over the polar lattice to satisfy the power constraint. Both the construction and shaping are explicit, and the overall complexity of encoding and decoding is $O(N\log N)$ for any fixed target error probability.Comment: full version of the paper to appear in IEEE Trans. Communication

Freshman Engineering Project on Energy Scavenging

This paper describes the design, development and implementation of an energy scavenging project for an introduction to engineering course. The overall objective of the project is to provide students with a hands-on experience on all the components of a renewable energy system. After completing this project students should be able to understand the basic engineering concepts as well as the principles of the design process. Energy scavenging is a form of renewable energy technology at micro or nano scale level. In this project students design and build a small vibrating system that takes the place of the energy source. A piezoelectric material is used to collect the energy produced by the vibrating system. The output of the piezoelectric material is fed to a rectifier circuit whose output charges a battery. Over two hundred freshman engineering students from four different disciplines: civil, computer, electrical, and mechanical have completed this project. Students’ reports, reflection papers, and the results from surveys clearly show that, in addition to be a very appealing project, its objectives are achieved

From a long-term dynamic perspective: how should internal carbon pricing be implemented?

Internal carbon pricing has the potential to positively influence enterprises’ carbon emissions. However, the strategies for implementing internal carbon pricing for enterprises and internal organizations remain unclear. In this study, employing a differential game research methodology, we design three implementation strategies for internal carbon pricing from a dynamic time perspective. Through comparative research and numerical analysis of these three different strategies’ effects on the changes in enterprise carbon emission reduction and goodwill, we find that for both enterprises’ carbon emission reduction and goodwill, Model C (implementing secondary investment for internal carbon fee collection) is optimal when the proportion of internal organizational revenue allocation is high and the proportion coefficient of internal carbon fee collection is low. When the proportion coefficient of internal carbon fee collection meets certain conditions, it makes the total profit of system under model C (implementing secondary investment for internal carbon fee collection) larger than the other two strategies. Due to short-sighted behavior, both enterprises’ profits and carbon emissions gradually decrease, leading to the internal carbon prices of enterprises under the three strategies will approach a stable value

Local Stability in the Process of Excavation Located in High Permeability Saturated Sand of Diaphragm Wall Construction

The stability of the slurry trench is very important in the construction of the underground diaphragm wall. In the current research, the local instability of the slurry trench is mainly investigated after the excavation of a unit slot is completely completed. However, the local stability in the process of excavation has received little attention. In this paper, the local stability in the process of excavation located in high permeability strata of diaphragm wall construction is investigated. A slurry infiltration experiment was carried out to investigate the distribution of the excess pore pressure in the high permeability strata, which can determine the effective support pressure. Then, the local stability of the slurry trench in the process of excavation located in high permeability saturated sand is calculated. The results show that the same types of sand according to the design code cannot be simply treated to have the same permeability and similar distribution of the excess pore pressure, since whether the filter cake can be formed and the quality of the filter cake are the key factors to determine the distribution of the excess pore pressure. This is also crucial for the local stability in the process of excavation located in high permeability saturated sand. It is suggested that attention should be paid to the local stability in the process of excavation located in high permeability strata when the slurry infiltration mode is the pure permeable zone