THE NSA PERSPECTIVE ON TELECOMMUNICATIONS PROTECTION IN THE NONGOVERNMENTAL SECTOR

This paper presents the travels of a cryptological Intelligence mission through Germany near the end of World War II to locate German Signal Intelligence information documents, and equipment.     

REVIEWS AND THINGS CRYPTOLOGIC

Abstract

This paper analyses the organization of the Government Code and Cypher School (GC &; CS) at Bletchley Park during the Second World War. The complexities and peculiarities of the organization are overviewed and a periodization provided. The main focus is on the pivotal 1942 reorganization, which is explained in terms of the changing scale of GC &; CS following the successful attack on the Enigma machine cipher, and in terms of organizational politics. The more minor 1944 reorganization is also described.     

NAVAL ENIGMA: SEAHORSE AND OTHER KRIEGSMARINE CIPHER BLUNDERS

Describes major weaknesses in a naval Enigma cipher codenamed Seahorse, and how it and similar naval Enigma ciphers were solved by US Navy codebreakers during WWII.     

L 1 Sensitivity minimization for plants with commensurate delays

In this paper we consider the problem ofL ¹ sensitivity minimization for linear plants with commensurate input delays. We describe a procedure for computing the minimum performance, and we characterize optimal solutions. The computations involve solving a one-parameter family of finite-dimensional linear programs. Explicit solutions are presented for important special cases.Notation X ^* Dual space of a normed linear spaceX - All elements inS with norm 1 - S The annihilator subspace defined as . - S The annihilator subspace defined as . - BV(X) Functions of bounded variation onX - C ₀(X) Continuous function on a locally compact spaceX such that for all > 0, {x X¦ ¦f(x)¦s is compact - C ^N (a, b) Vectors of continuous functions on (a, b) The authors acknowledge support from the Army Research Office, Center for Intelligent Control, under grant DAAL03-86-K-0171, and the National Science Foundation, under grant 8810178-ECS.     

A spectral characterization of H-optimal feedback performance and its efficient computation

We study the spectral properties of a ‘Toeplitz⁺ Hankel’ operator which arises in the context of the mixed-sensitivity H^∞-optimization problem and whose largest eigenvalue characterizes the optimal achievable performance ε₀. The existence of such an operator was first shown by Verma and Jonckheere [26], who also'noted the potential numerical advantage of computing eo through its eigenvalue characterization rather than through the ε-iteration. Here, we investigate this operator in detail, with the objective of efficiency computing its spectrum. We define an ‘adjoint’ linear-quadratic problem that involves the same ‘Toeplitz⁺ Hankel’ operator, as shown by Jonckheere and Silverman [13–16]. Consequently, a finite polynomial algorithm allows ε₀ to be characterized as simply as the largest root of a polynomial. Finally, a computationally more attractive state space algorithm emerges from the H^t8/LQ relationship. This algorithm yields a very good accuracy evaluation of the performance ε₀ by solving just one algebraic Riccati equation. Thorough exploitation of this algorithm results in a drastic computation reduction with respect to the standard e-iteration.     

融合残差上采样结构的P2Net无监督单目深度估计

单目深度估计是计算机视觉领域中的一个基本问题,面片匹配与平面正则化网络(P²Net)是现阶段最先进的无监督单目深度估计方法之一.由于P²Net中深度预测网络所采用的上采样方法为计算过程较为简单的最近邻插值算法,使得预测深度图的生成质量较差.因此,本文基于多种上采样算法构建出残差上采样结构来替换原网络中的上采样层,以获取更多特征信息,提高物体结构的完整性.在NYU-Depth V2数据集上的实验结果表明,基于反卷积算法、双线性插值算法和像素重组算法的改进P²Net网络相较原网络在均方根误差RMSE指标上分别降低了2.25%、2.73%和3.05%.本文的残差上采样结构提高了预测深度图的生成质量,降低了预测误差.     

How efficiently can room at the bottom be traded away for speed at the top?

Given exponential 2 ⁿ space, we know that an Adleman-Lipton computation can decide many hard problems – such as boolean formula and boolean circuit evaluation – in a number of steps that is linear in the problem size n. We wish to better understand the process of designing and comparing bio-molecular algorithms that trade away weakly exponential space to achieve as low a running time as possible, and to analyze the efficiency of their space and time utilization relative to those of their best extant classical/bio-molecular counterparts. We propose a randomized framework which augments that of the sticker model of Roweis et al. to provide an abstract setting for analyzing the space-time efficiency of both deterministic and randomized bio-molecular algorithms. We explore its power by developing and analyzing such algorithms for theCovering Code Creation (CCC) and k-SAT problems. In the process, we uncover new classical algorithms for CCC andk-SAT that, while exploiting the same space-time trade-off as the best previously known classical algorithms, are exponentially more efficient than them in terms of space-time product utilization. This work indicates that the proposed abstract bio-molecular setting for randomized algorithm design provides a logical tool of independent interest. This revised version was published online in June 2006 with corrections to the Cover Date.     

Queuing system evolution in a diffusion approximation scheme

An asymptotic diffusion approximation scheme is investigated as applied to the requirement evolution in semi-Markov queuing systems. In proving the diffusion approximation theorem, the compensating operator of the corresponding extended Markov process is used. This problem is solved with the help of a phase merging procedure. Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 136–145, May–June 2009. Original article submitted August 19, 2008.     

THE DIPLOMACY OF SECURITY: BEHIND THE NEGOTIATIONS OF ARTICLE 18 OF THE SINO-AMERICAN COOPERATIVE AGREEMENT

In early February, 1942, Commander M. E. Miles proposed the establishment of a radio intelligence unit in China. His proposal led to the creation of Naval Group China (NGC), the umbrella organization for units that performed weather forecasting, advised and trained Chinese guerillas, and intercepted and analyzed Japanese radio traffic. NGC was part of the Sino-American Cooperative Organization (SACO). Most of the commitments of China and NGC were formalized on 15 April 1943 with the signing of the Sino-American Cooperative Agreement (SACO). Article 18 required further delicate negotiations between Miles and General Tai Li, head of the Bureau of Investigation and Statistics (China's secret service). Miles was soon trapped between his commitment to Tai Li and Joseph Wenger's concern that any intercepted traffic shared with the Chinese would quickly become available to the Japanese via insecure Chinese codes. Fleet Radio Unit, China (FRUCHI) resolved this dilemma.     

ALAN TURING'S VISIT TO DAYTON

Recently declassified documents from the “Crane Collection” at the National Archives (USA) reveal much of the purpose of Alan Turing's visit to the United States during the Winter of 1942–1943. The “Bombe Correspondence” file contains Turing's “Visit To National Cash Register Corporation of Dayton, Ohio” and additional material which places this report and his earlier “Treatise on the Enigma” in the context of his role as consultant to the U. S. Navy Cryptanalytic Section (Op-20-G) on the design of the Navy Bombe and other related matters. The documents in this collection reveal a productive and decisive relationship between Turing and Op-20-G dating from the visit of the Sinkov mission to Bletchley Park in February 1941.