Turing test, easy to pass; human mind, hard to understand

Under general assumptions, the Turing test can be easily passed by an appropriate algorithm. I show that for any test satisfying several general conditions, we can construct an algorithm that can pass that test, hence, any operational definition is easy to fulfill. I suggest a test complementary to Turing's test, which will measure our understanding of the human mind. The Turing test is required to fix the operational specifications of the algorithm under test; under this constrain, the additional test simply consists in measuring the length of the algorithm

Gastric Adenocarcinoma Presenting as Chronic Back Pain: A Case Report

Introduction: Early stage gastric cancer is usually asymptomatic. It is not until later stages of the disease, usually with metastasis, that patients typically develop symptoms that would prompt further evaluation.Case Report: We present a case of a patient with chronic back pain who was found to have a gastric antral mass as the etiology of her pain. The patient proceeded to have a partial gastrectomy with complete surgical excision of her early-stage gastric cancer, after which her chronic back pain resolved.Conclusion: This case demonstrates the importance of considering significant pathology in patients presenting with chronic complaints to the emergency department

Re-visiting the One-Time Pad

In 1949, Shannon proved the perfect secrecy of the Vernam cryptographic system,also popularly known as the One-Time Pad (OTP). Since then, it has been believed that the perfectly random and uncompressible OTP which is transmitted needs to have a length equal to the message length for this result to be true. In this paper, we prove that the length of the transmitted OTP which actually contains useful information need not be compromised and could be less than the message length without sacrificing perfect secrecy. We also provide a new interpretation for the OTP encryption by treating the message bits as making True/False statements about the pad, which we define as a private-object. We introduce the paradigm of private-object cryptography where messages are transmitted by verifying statements about a secret-object. We conclude by suggesting the use of Formal Axiomatic Systems for investing N bits of secret.Comment: 13 pages, 3 figures, submitted for publication to IndoCrypt 2005 conferenc

On Hilberg's Law and Its Links with Guiraud's Law

Hilberg (1990) supposed that finite-order excess entropy of a random human text is proportional to the square root of the text length. Assuming that Hilberg's hypothesis is true, we derive Guiraud's law, which states that the number of word types in a text is greater than proportional to the square root of the text length. Our derivation is based on some mathematical conjecture in coding theory and on several experiments suggesting that words can be defined approximately as the nonterminals of the shortest context-free grammar for the text. Such operational definition of words can be applied even to texts deprived of spaces, which do not allow for Mandelbrot's ``intermittent silence'' explanation of Zipf's and Guiraud's laws. In contrast to Mandelbrot's, our model assumes some probabilistic long-memory effects in human narration and might be capable of explaining Menzerath's law.Comment: To appear in Journal of Quantitative Linguistic

Secure communication in IP-based wireless sensor network via a trusted gateway

As the IP-integration of wireless sensor networks enables end-to-end interactions, solutions to appropriately secure these interactions with hosts on the Internet are necessary. At the same time, burdening wireless sensors with heavy security protocols should be avoided. While Datagram TLS (DTLS) strikes a good balance between these requirements, it entails a high cost for setting up communication sessions. Furthermore, not all types of communication have the same security requirements: e.g. some interactions might only require authorization and do not need confidentiality. In this paper we propose and evaluate an approach that relies on a trusted gateway to mitigate the high cost of the DTLS handshake in the WSN and to provide the flexibility necessary to support a variety of security requirements. The evaluation shows that our approach leads to considerable energy savings and latency reduction when compared to a standard DTLS use case, while requiring no changes to the end hosts themselves