Doubles and Negatives are Positive (in Self-Assembly)

In the abstract Tile Assembly Model (aTAM), the phenomenon of cooperation occurs when the attachment of a new tile to a growing assembly requires it to bind to more than one tile already in the assembly. Often referred to as ``temperature-2'' systems, those which employ cooperation are known to be quite powerful (i.e. they are computationally universal and can build an enormous variety of shapes and structures). Conversely, aTAM systems which do not enforce cooperative behavior, a.k.a. ``temperature-1'' systems, are conjectured to be relatively very weak, likely to be unable to perform complex computations or algorithmically direct the process of self-assembly. Nonetheless, a variety of models based on slight modifications to the aTAM have been developed in which temperature-1 systems are in fact capable of Turing universal computation through a restricted notion of cooperation. Despite that power, though, several of those models have previously been proven to be unable to perform or simulate the stronger form of cooperation exhibited by temperature-2 aTAM systems. In this paper, we first prove that another model in which temperature-1 systems are computationally universal, namely the restricted glue TAM (rgTAM) in which tiles are allowed to have edges which exhibit repulsive forces, is also unable to simulate the strongly cooperative behavior of the temperature-2 aTAM. We then show that by combining the properties of two such models, the Dupled Tile Assembly Model (DTAM) and the rgTAM into the DrgTAM, we derive a model which is actually more powerful at temperature-1 than the aTAM at temperature-2. Specifically, the DrgTAM, at temperature-1, can simulate any aTAM system of any temperature, and it also contains systems which cannot be simulated by any system in the aTAM

Spartan Daily, March 23, 1984

Volume 82, Issue 38https://scholarworks.sjsu.edu/spartandaily/7156/thumbnail.jp

Spartan Daily, February 23, 1981

Volume 76, Issue 19https://scholarworks.sjsu.edu/spartandaily/6723/thumbnail.jp

An investigation of the needs and the design of an orbiting space station with growth capabilities

An architectural approach to the evolutionary growth of an orbiting space station from a small manned satellite to a fully independent, self-sustainable space colony facility is presented. Social and environmental factors, ease of transportation via the space shuttle, and structural design are considered

Spartan Daily, March 20, 1974

Volume 62, Issue 22https://scholarworks.sjsu.edu/spartandaily/5845/thumbnail.jp

Statistical Tools for Linking Engine-Generated Malware to Its Engine

Malware-generating engines challenge typical malware analysts by requiring them to quickly extract and upload to their customers\u27 machines, a signature for each of a possi- bly vast number of never-before-seen malware instances that an engine can generate in a short amount of time In this thesis we propose and evaluate two methods for\u27linking va- riants of engine-generated malware to its engine. The proposed methods use the w-gram frequency vector (NFV) of the opcode mnemonics of an engine-generated malware in- stance as a feature vector for the instance. An NFV is a tuple that maps «-grams with their frequencies. The in-formation contained within the NFV of an engine-generated malware instance is then used to attribute the instance to the engine. The first method im- plements a Bayesian-like classifier that uses 1-gram frequency vectors of programs as feature vectors. This method was successfully evaluated on a sample of benign programs and one of malicious programs from the W 3 2. Simile family of self-mutating mal- ware. The second method, which is an extension of the first method, uses optimized 2-gram frequency vectors as feature vectors and classifies malware by computing its proximity to the average of the NFVs of instances known to have been generated by a known engine. The second method was successfully evaluated on four ma) ware-generating engines: W32 . Simile, W32.Evol, W32.NGCVK, and W32.VCL. The evaluation yielded a set of four 1 7-tuples of doubles as signatures for each of the en- gines, and achieved a 95% discrimination accuracy between a sample of benign programs and samples of malware instances that were generated by these engines. Accuracies of 94.8% were achieved for engine signatures of size 6. 8 and, 14 doubles. We also used four k-rm classifiers which, unlike the second method, require the time-consuming task of creating and storing one signature per known malware instance, to countercheck the ac- curacies achieved by the second method. This work is inspired by successful methods for attributing natural language texts to their respective authors. The proposed methods may be viewed as filtering (or decision support) tools that malware detectors may use to de- termine whether extensive engine-specific program analyses such as emulation and con- trol tlow analysis are needed on a suspect program

Black & White Photography for 35mm: A Guide to Photography and Darkroom Techniques

Combining detailed explanations of all aspects of black-and-white 35mm photography with exercises that clearly illustrate each concept step-by-step results in a comprehensive how-to guide to the camera and darkroom. This manual covers the basics of taking a shot by explaining the camera functions, how the camera meters light, and the proper use of filters. It teaches beginning through advanced techniques for shooting, developing, and printing and offers advice on selecting the right lens, the proper depth of field, and correct exposure. Included are darkroom tips on setup and maintenance and details of the latest technology and equipment.https://digitalcommons.lmu.edu/lmu_ebook_collection/1001/thumbnail.jp