Engineering, Technology & Applied Science Research

216-220

Authors: M. Seifouri, M. M. Karkhanehchi, S. Rohani

The main goal in this paper is to design single-mode optical fibers for DWDM networks, which are used today in rapid communications. These networks require low dispersion in a wide range of wavelengths. So, in this paper, multi-layer optical fibers with low dispersion value and flat dispersion slope in wavelength range of 1.5-1.6µm) are designed, using optimization algorithms.

226-231

Authors: N. Bagheri

In this paper, the existence of multicollisions in Zipper Hash structure, a new Hash structure which was introduced to strengthen the iterated Hash structures, is presented. This study shows that finding multicollisions, i.e. 2k-way collision, in this Hash structure is not much harder than finding such multicollisions in ordinary Merkle - Damgard (MD) structure. In fact, the complexity of the attacks is approximately n/2 times harder than what has been found for MD structures. Then, these large multicollisions are used as a tool to find D-way preimage for this structure. The complexity of finding 2K-way multicollisions and 2k-way preimages are (eq) and (eq) respectively. Similar to what has been proved by Joux for MD, it is shown in this paper that this structure could not be used to create a Hash function with 2n-bit length by concatenating this structure with any other Hash structure by Hash’s output length of n-bite. It is also shown that time complexity of finding a collision for this concatenated structure is (eq) which is much smaller than what was expected from generic-birthday attack which would be (eq) . In addition, it is shown that increasing the number of rounds of this Hash function can not improve its security against this attack significantly and the attacker can find multicollisions on this Hash function which means that this Hash function has a structural flaw.

237-240

Authors: F. E. Idachaba, E. M. Idachaba

The lack of access to quality healthcare and the lack of sufficient manpower, especially doctors, in rural areas is a major healthcare challenge faced by dwellers in rural communities in most developing countries. The intervention of governments, which range from the introduction of training programs aimed at producing health workers from schools of health technology and nursing to the recalling and deployment of retired nurses to rural areas, has still not been able to generate the desired improvement in healthcare delivery, as outbreaks of epidemics are still being reported in such areas. This work presents an E-Health architecture which utilizes low cost sensors and communication devices to link the doctors in the urban areas with the patients in rural areas enabling doctors-patients interaction. The system enables accurate and timely diagnosis of the patients and facilitates proper treatment plans. It also incorporates an epidemic alert which enables the tracking of diseases and the early detection and control of epidemics.