Advanced Defense Science and Technology
Year:2011 | Volume:2 | Issue:3 (5)|Papers Count:9

Analysis and evaluation of urban infrastructures treatment is of vital importance in natural disasters management. Among them, performance analysis of communication network, due to the extensive role in the cycle of crisis management and especially in relief stage, can have an important influence on the identification of vulnerable areas. Moreover, it results in faster relief and thus reduces the casualty. In this paper, the classification of the performance of communication network in Khaksefid area (as one of the erosion texture neighborhoods with spontaneous origin) during and after earthquake through identification of vulnerability criteria of communication network in the local scale is addressed and vulnerable areas are identified. The results show that in the study area, some of the roads have higher degree of vulnerability, and they will have very low efficiency at time of crisis and after. Therefore, it is necessary to repair the communication network and some other infrastructures and until repairing, use another road for relief in these cases.

One of the objectives defined in the facility location problem is the maximum dispersing facility location. In these issues, the goal is maximizing the distance between the facilities according to the available constraints. In some cases these issues use the location of radio stations, schools, sales representatives and general location with sensitive facilities which have much application in passive defense principles. On the other hand, the facilities operating one principle of passive defense should be dispersed. Therefore, they should be established in a place where they can gain their mission correctly. As a result, the coefficient errors are reduced. Considering this issue (coefficient of performance and reduced error of candidate points), we suggest Data Envelopment Analysis with the criteria to choosing locations with efficient distribution model. So, in this paper a new multi-objective model for locating critical and important facilities considering passive defense principles is presented.

In this paper, we proposed a new block cipher algorithm called MMF2 suitable for embedded applications, employing a new linear and differential cryptanalysis method. The proposed algorithm has 64 bit block length and 80 bit key size with 9-round iteration. The main structure of this algorithm is Fiestel network that uses generalized type II Fiestel for its round function. The algorithm's design afford provable security with 2-111.6 and 2-94.98 linear and differential characteristics, respectively. We used SDS structures in designing nonlinear function of algorithm. This algorithm has a provable security and simple implementations for 9-round iteration. According to simplicity and security features of substitution box with algebraic degree of 6 and nonlinear degree of 96, this algorithm is suitable for wireless sensor networks.

Time Reversal (TiR) technique mitigates the complexity of receiver in UWB indoor channels, but is very sensitive to the channel estimation error. The effect of channel imperfection on TiR technique is considered in this paper. At first, the Bit Error Probability (BEP) of the TiR-UWB communication system under the assumptions of the simple Matched Filter (MF) receiver with the channel estimation errors is derived in closed-form. Moreover, based on optimal MMSE estimator receiver, a pre-filter is calculated in closed-form to improve the performance of the TiR-UWB system in an imperfect CSI scenario. Furthermore, a two stage iteration-based algorithm is developed at transmitter to calculate a pre-filter in MF receiver. This improved algorithm causes the channel estimation error tends to zero in some steps for the TiR-UWB system with MF. The initial value for this iteration-based improved algorithm is considered to be closed form pre-filter calculated in TiR-UWB system with optimal MMSE estimator. Finally, exhaustive simulations are done to demonstrate the performance advantage attained by the improved algorithm.

Sevoflurane is a new inhalation anesthetic that because of its unique characteristics is very interesting and it’s usage is developped. Different methods have been reported for its synthesis, the best one being a two- step method. In the first step, 1, 1, 1, 3, 3, 3-hexafluoro-2-propanol (HFIP) reacts with AlCl3 and trioxane to produce sevochlorane. In the second step, sevochlorane reacts with KF in PEG -400 and sevoflurane is obtained. In this research, the amounts of PEG-400, KF and reaction time have been optimized (PEG-400 to SVC (2.5:1 V/V), KF to SVC (1.2:1 mol/mol), T=90-95°C and t=2.5 h) and sevofluorane was obtained in 90% yield. Also, ionic liquids were used as green solvent. It was found out that fluorination reaction of sevochlorane with KF can also be performed in ionic liquids, but, howevere, with lower yields. The maximum yield was achieved by the use of tetrabutylammoniumfluoride ionic liquid TBAF in 20% yield.

Dichloramine resin has been synthesized in three steps by using cation-exchange resin as precursor for chemical warfare agent decontamination. The product of each step was characterized by FT-IR. The active chlorine in final product was obtained about 9-11%, using iodometric titration. The resin efficacy as a decontaminator has been investigated by treating it with 2-chloroethyl phenyl sulfide (mustard simulant) at ambient temperature and the degradation products; i.e. hydroxyethyl phenyl sulfone and diphenyl disulfide have been identified using a GC-MS instrument.

One of the passive defense topics is the retrofitting of structures under explosive effects. The water medium has more effect on submarine and marine structures subjected to explosion. Having large marine border in our country, it is necessary to study these phenomena. Regarding the geometrical shape of submarine and marine infrastructure, there are lots of studies concerning the flat and cylindrical plates. In this paper the effect of charge weight and standoff on plate deformation have been studied using ABAQUS / Explicit software and the results have been accurately confirmed when compared with available reported experimental results and relationships. Simulation methods, coefficients and parameters used in this paper can be used in the case of study and simulation of structure response subjected to underwater explosion load. By verification of conducted simulation, the initial design of cylindrical test chamber in two states without stiffener and with stiffener under the effect of underwater explosion load has been assessed. By design of chamber using stiffener, the weight of chamber and effective cost are reduced considerably.

Despite the fact that using the services of outsourced data stream servers has extremely been welcomed, but still the problem of obtaining certainty about received results from these servers is one of the basic challenges in enterprises. For outsourcing these services, the user should be assured by a mechanism about the security of communication channels as well as the correct and honest function of the server, because the server may attack the integrity of the results due to economic and malicious reasons. In such attacks, some parts of results are not sent to the user or sent after being modified or delayed. In this article, we have come up with an efficient method for detecting integrity attacks in outsourced data steam systems based on auditing the results of cross computation. In this method, the main data stream has been enciphered by a key and a small part of data has been enciphered by a different key, as a dependant data stream, and sent to the server. The requested query is applied on both streams and the user judges the integrity of results by comparing the results. Our method imposes a little overhead on the user and needs no change in the structure of the server. The probabilistic modeling of the method shows that this method has a high efficiency and the results of the exprimental analysis confirm this very well.

In different fields, including military industries, for whether military forces or military armament, camouflage is of high importance. The question is which camouflage pattern, in what size, with which color composition is more suitable for soldier’s camouflage, in a specific environment. The performance of camouflage patterns are usually estimated by on the time needed for recognizing the concealed object. This effort is seeking to prepare a computer software to answer such questions. Having images of camouflage Environment, Pattern & Object, this software designs a test; The result of each test is the “mean recognition time” among the background image. The prepared software has advanced features such as zoom background image, change size, angle, color and camouflage schemes, blur the edges of the object, the size of an object to be camouflaged, and so on. The results were analysed several times and through different ways, and are compatible with the proved principles of camouflage issue.