فصلنامه پدافند غیرعامل
سال سوم شماره 1 (پیاپی 9، بهار 1391)

The armed forces projects dealing with explosives continue to face two foreign and internal threats. The foreign threat may originate from an enemy or local subversion and the internal threat may take place due to the nature of its material and explosives. In this article the local threat is introduced and scrutinized. The necessary provisions to reduce damage in these kinds of projects are discussed and reviewed. This article reviews ways of reducing damage by properly utilizing architectural design and following the basic definitions and concepts, provisions about architectural design of ammunition dumps, barrier walls and embankments and the location and buildings using rejecting ceiling and walls and finally, the necessities of architectural design of spaces where explosion may take place, have been explained which when implemented, will be effective in preventing explosion incidents and reducing damage resulting from these accidents.

Bioterrorism includes the abuse of biological agents to terrorize or kill people and destroy livestocks or plants. Nowadays with the improvement in biological science, bioterrorism has broader range and modern dimensions such as the use of pathogenic microorganisms and their toxins. One of the most potent microbial agents that has military applications is the bacteria called shigella. Shigellosis is an infectious disease that is highly contagious and is accompanied by lethargy, malaise, diarrhea, fever, nausea, vomiting, stomach ache, blood and mucus and pus in excrement. Several factors and properties in shigella have caused it to be considered as a potent bacteria used for biological warfare. The major reasons to use shigella in bioterrorism applications include: 1- The lower infectious dose, 2- Presence of multiple infectious ways, 3- Increasing drug resistance therapeutic agents, 4- High spreading power and causing secondary infections in population, and 5- Higher mortality rate in comparison with other bacteria in its family. One of the best ways to counter shigella is to produce protective vaccine against it, in regard to the problems in the production of efficient vaccines, choosing the best agent for the appropriate and viable stimulation of the immune system is of utmost importance. Nowadays with the advancement and developments of genetic engineering technologies, new concepts for producing live vaccines with less or no pathogenesis based on the deletion of effective genes in development of disease in target bacteria have been introduced that seem to be as a promising tool to counter shigellosis. In this study, in addition to a quick analysis of bioterrorism from different angles, various ways and the different kinds of vaccine made against shigella have been scrutinized to counter it.

Increasing developments of fields of communication, telecommunication and data recognition and assembly system have caused considerable military challenges. It is assumed that security in data transactions is a critical factor in passive defense and cryptography science plays an undeniable role in this scenario. Therefore, Statistical improvement of a native stream cipher was accomplished with discrete and permutated chaotic mapping which could be utilized for increased safety of confidential data transactions in passive defense. Weakness of nonlinear part was resolved in this cipher compared to old one. This enhanced performance and power of the encryption.

The cost of hardening of buried structures and construction and exploitation of deeply buried structures as well, is very high and on the other hand, the mechanisms for detection, recognition and destruction of Buried Structures are in everyday development. While this is a great challenging subject for utilizing these structures we need to review our safety plans. Jamming & CCD plans are some of the main branches of passive defense that cause the increase of munitions error CEP (Circular Error Probable) and can be used for proofing the performance of buried structures. In this paper we introduce the "Functional Availability" for the main measure of performance and also Jamming & CCD and hardening performance for a sample shallow buried structure is calculated and compared. The main axes of discussion in this paper are:•Governing restrictions over observability and vulnerability of buried structures•Opportunities and threats governing detection, identification and destruction of buried structures•Basic calculation of performance for passive defense plans on the basis of Functional Availability •Comparison between levels of effectiveness of hardening methods and Jamming & CCD plans

Covert channel means communicating information through covering of open and authorized channel in a manner that the existence of the channel is rendered hidden. Network covert channels have many malicious and authorized applications which intend to hide communication. Network covert channels are divided into two categories called Covert Storage and Covert Timing channels. Covert channels have three performance evaluation criteria; capacity, robustness and stealth. Covert channel countermeasure methods are elimination, limitation and detection of channel.Use of covert channel is an appropriate solution for secure communication in networks for passive defense applications. On the other hand, detection and countering unauthorized covert channels is necessary to defend networks. This paper describes applications and taxonomy of covert channels and presents performance evaluation criteria and countermeasure methods.

Considering the terrorist and hostile threats against Iran and the dire need of passive defense in structures to reduce casualty and financial damage caused by implosion and explosion in structures, reviewing the performance of structures against blast is of utmost importance. One of the most important structural members which severely affect the overall performance of the structure is the connection of pole to the pillar. The inappropriate performance and defect of these connections can contribute to the surface and in subsequent steps cause the increasing defect in structures and its collapse. In this article, the blast loading effect on the performance of connections of pole to twist shielding pillar has been studied. This kind of connection is used in steel structures in Iran. To do the research, the Limited Elements Method and the ABAQUS software which is one of the most robust Limited Elements Method that exists today was used. To ensure the results of Limited Elements modeling, the authenticity of the model using the results of a laboratory research was first utilized and an appropriate compliance between the predicted results by the Limited Elements Method and the measured results in the laboratory were observed. After ensuring the precision of the Limited Element in the simulation of the connection behavior, a non-linear dynamic analysis taking into account the effects of high rate strain resulting from blast, was performed. Due to the presence of symmetry, only 1/8 of the room was studied for the modeling. The weight of the explosive approximated 15 kilograms of TNT. The test results showed that the occurrence of blast inside the room causes a twisting deflection in the pole. It was also noticed that this kind of connection has a relatively formable behavior against blast loading.

Global positioning system (GPS) is one of the targets that could potentially be attacked by electronic warfare systems. Disruption of this system for countries which dependent on it could be devastating. In this regard, a native positioning system for a country can play a significant role in reducing this damage. Today, despite having several different satellite systems, including GPS, the use of backup system is a necessity.In this paper, we describe a system which works with the GPS but independently with a perfect precision. This system carries out positioning and navigation functions.The purpose of this paper is to review the overall design of a positioning system, with a passive user, rapid positioning, sufficient coverage, and acceptable accuracy for different distances. The system can also be designed transportable so that in crisis times, it is possible to move quickly. Finally, we explain the use of data fusion by Kalman filter for this system.