Non-Adaptive Coding for Two-Way Wiretap Channel with or without Cost Constraints

This paper studies the secrecy results for the two-way wiretap channel (TW-WC) with an external eavesdropper under a strong secrecy metric. Employing non-adaptive coding, we analyze the information leakage and the decoding error probability, and derive inner bounds on the secrecy capacity regions for the TW-WC under strong joint and individual secrecy constraints. For the TW-WC without cost constraint, both the secrecy and error exponents could be characterized by the conditional R\'enyi mutual information in a concise and compact form. And, some special cases secrecy capacity region and sum-rate capacity results are established, demonstrating that adaption is useless in some cases or the maximum sum-rate that could be achieved by non-adaptive coding. For the TW-WC with cost constraint, we consider the peak cost constraint and extend our secrecy results by using the constant composition codes. Accordingly, we characterize both the secrecy and error exponents by a modification of R\'enyi mutual information, which yields inner bounds on the secrecy capacity regions for the general discrete memoryless TW-WC with cost constraint. Our method works even when a pre-noisy processing is employed based on a conditional distribution in the encoder and can be easily extended to other multi-user communication scenarios

The Analysis on Multimodal Transport Mode of Cross-border E-commerce with \u27the Belt and Road\u27 Strategy Based on Personalized Recommendation

With the further advance of \u27the Belt and Road\u27 strategy , China\u27s cross-border E-commerce has obtained powerful policy support and wide world market. But from the view of users\u27 coverage and total import and export of the trade along \u27the Belt and Road\u27 , China\u27s cross-border E-commerce still has great potential for development, while the high transportation cost is the main resistance in business. Therefore, based on the theory of customer personalized recommendation, combining with the successful cases of personalized services recommendation system from Jingdong and eBay, this article puts forward the multimodal transport service mode of China\u27s cross-border logistics enterprises so as to customize the optimized logistics service system for e-commerce and achieve a win-win situation for customers and enterprises

Primary isolated intracranial Rosai–Dorfman disease: Report of a rare case and review of the literature

Background Intracranial involvement is an uncommon manifestation of Rosai–Dorfman disease (RDD) and had been rarely reported. In this study, we explore clinical characteristics, imageology manifestations and pathological features of primary intracranial RDD so as to improve the understanding for this disease. Methods One case (16-years-old boy) with primary intracranial RDD was analyzed and studied retrospectively by MRI features, histopathological observation and immunohistochemical staining, and the related literatures were reviewed. Results The case was single lesion and involved the dura of the left middle cranial fossa base, which was iso-hypo signal intensity on T1WI and hypointense on T2WI and FLAIR image. The lesion was a homogeneous contrast enhancement mass with dural tail sign and had peritumoral brain edema. Pathological analysis showed the lesion consisted of variable numbers of mature lymphocytes, plasma cells and neutrophils. The characteristic histiocytes were emperipolesis and positively expressed for S-100 and CD-68 and negatively expressed for CD-1a by immunohistochemical analysis. Based on clinical presentations and histological findings after surgical excision, a final diagnosis of primary intracranial RDD was made. Conclusion Primary intracranial RDD, especially located in the cranial base, is exceptionally rare, which hard to be distinguished with meningoma by imageology and clinical manifestations, but could be diagnosed by pathological and immunohistochemical examinations. Surgery is of the most importance treatment and prognosis is optimistic for this disease

Wiretap channel with side information

In this thesis, we consider a communication problem over the wiretap channel, where one wants to send a message to the legitimate receiver and at the same time keep it from the wiretapper as secret as possible. Due to known results, the theory on the model of the wiretap channel where side information is not present, is fairly complete. Introducing side information noncausally known at the transmitter into the model, we wonder whether side information could help the secret communication over the wiretap channel. We investigate the wiretap channel with side information and explore its security capacity and capacity region. For the discrete memoryless case, we establish a coding theorem, which implies an achievable rate equivocation region and a bound for the secrecy capacity. In particular, the secrecy capacity is determined for some special cases. Extending our result for the discrete memoryless case to the Gaussian case, our contribution to the Gaussian wiretap channel with side information is twofold. First, we derive an achievable rate equivocation region by applying Costa's strategy, which improves an earlier result given by Mitrpant. Compare it with the capacity region for the corresponding Gaussian wiretap channel given by Leung-Yan-Cheong and Hellman. We show that for the Gaussian wiretap channel, side information helps to achieve a larger secrecy capacity and a larger capacity region. Thus we can draw a conclusion that side information plays a positive role in the secret communication over the Gaussian wiretap channel. Furthermore, we generalize Costa's strategy by taking the correlation coe±cient of the codeword and side information as another parameter into our consideration. We show that the achievable region derived by applying Costa's strategy can be enlarged by applying the generalized Costa's strategy. In other words, for the Gaussian wiretap channel, it can be a better choice to send a codeword dependent on the side information, in order to yield a higher rate at a certain security level. In addition, we give the optimum choice of the parameters for the generalized Costa's strategy to achieve the maximal rate at perfect secrecy. In this thesis, we also investigate the problem of developing forward coding schemes for secure communication over the wiretap channel. A code construction is considered for the specific case when both the main channel and the wiretap channel are binary symmetric. Theoretically, we show that its secrecy capacity can be achieved by using random linear codes. For practical purpose, we evaluate the performance of the coding schemes when specific linear codes are used in the construction. As an application, we reformulate the security problem in biometrics as a communication problem over the wiretap channel. We review two fuzzy commitment schemes, one by Juels and Wattenberg and the other by Cohen and Zémor. We characterize the performances of both schemes with the terminologies for the wiretap channel. For the Juels-Wattenberg scheme, we give a security proof in the information theoretic sense. For the Cohen-Zémor scheme, we consider its practicality and give some insight into the choice of the parameters that yields good performance

ICT USE AND IDENTITY FORMATION AMONG BEIJING'S RURAL-TO-URBAN GRADUATE WORKERS

Master'sMASTER OF ART