Statistical analysis and compression of DNA using weighted probability approach and modified run-length encoding

Rapid advancements in research in the field of DNA sequence discovery has led to a vast range of compression algorithms. The number of bits required for storing four bases of any DNA sequence is two, but efficient algorithms have pushed this limit lower. With the constant decrease in prices of memory and communication channel bandwidth, one often doubts the need of such compression algorithms. The algorithm discussed in this paper hence not only compresses the DNA sequence, but also allows one to generate finite length sequences, which can be used to find approximate pattern matches. DNA sequences are mainly of two types, Repetitive and Non-Repetitive. The compression technique used is meant for the non-repetitive parts of the sequence, where we make use of the fact that a DNA sequence consists of only 4 characters. The algorithm achieves bit/base ratio of 1.3 - 1.4(dependant on the database), but more importantly one of the stages of the algorithm can be used for efficient discovery of approximate patterns. Copyright © 2007 IICAI

Selective querying and other proposals for a less congested Gnutella network

Network congestion and look-up times are of prime concern in peer-to-peer networks and Gnutella is no exception to this problem. A number of proposals and suggestions have been made to improve the scalability and performance and to reduce the congestion in Gnutella networks. An improvement would be to query a subgroup of positive respondents of the PING message that is exchanged among peers prior to the QUERY message. We discuss possible ways in order to determine "profitable". peers which could result in a successful transfer of a requested file and further highlight issues which we think would reduce congestion in the network. © Springer-Verlag Berlin Heidelberg 2007

Analysis Of Mechanisms Responsible For The Formation Of Dark Spots In Organic Light Emitting Diodes (Oleds): A Review

Organic Light Emitting Diode (OLED) is a new promising technology in lighting and display applications due to the advantages offered by the organic over inorganic materials. Nevertheless, the devices poor environmental stability and growth of dark spots has been a major concern for OLED devices. Based on the past literatures, several failure mechanisms have been proposed, suggesting that there is no particular model for the mechanisms of dark spots formation. In addition, the formation of dark spots is relatively obscure and unpredictable. On top of that, comprehensive reviews on the dark spots formation mechanism and the prevention methods are very limited at the current moment. Yet, both information are truly critical to be obtained and understood for OLED future development works. Thus, this paper reviewed particularly on the root cause formation of dark spots mechanisms in OLED devices. The dark spots are mainly formed due to the presence of foreign impurities and pinholes, as well as due to high current intensity. These root factor of elements will further enhance the degradation of OLED via bubble formations, electro-migrations, crystallizations and many other damaging processes. A few prevention steps have been discussed in order to reduce and prevent the dark spots from occurring such as the proper material selection and conducting the fabrication process in a controlled environment