Rings of protection

Security layers of protection Also known as concentric rings of protection, a concept of providing multiple independent and overlapping layers of protection in depth. For security purposes, this may include various layers of protection such as countersurveillance, counterintelligence, physical security, and cyber security. 

A complete security design includes these four concepts in layers of protection or a defense in depth arrangement. The most critical assets should be placed in the center of conceptual concentric levels of increasingly more stringent security measures. In the concept of rings of protection, the spatial relationship between the location ofthe target asset and the location ofthe physical countermeasures is important. 

In the case of malicious acts, the layers or rings of protection must be particularly robust because the adversaries are intentionally attempting to breach the protective features and can be counted on to use whatever means are available to be successful. This could include explosions or other initiating events that result in widespread common-cause failures. Some particularly motivated adversaries might commit suicide while attempting to breach the security layers of protection. 

The ozone layer around the Earth has provided us all a natural ring of protection from harmful UV radiation. However, multiple anthropogenic activities have acted as barriers and often caused damage to this shield. Less protection from UV light will, over time, lead to increased health problems and crop damage. Major health problems linked to overexposure to UV radiation by the depletion of ozone include skin cancer (melanoma and nonmelanoma), premature aging of the skin and other skin problems, cataracts and other eye damage, and suppression of normal immune system function.29... 

Counter combinations with anticoincidence circuit (measuring counter surrounded by a ring of protective counters which lower the zero effect). 

Security tends to emphasize rings of protection, meaning that, if possible, the most important or most vulnerable assets should be placed in the center of concentric levels of increasingly stringent security measures. For example, where feasible, a chemical facility s control room should not be placed right next to the building s reception area rather, it should be located deeper within the site so that, to reach the control room, an intruder would have to penetrate numerous rings of protection, such as a fence at the property line a locked exterior door an alert receptionist an elevator with key-controlled floor buttons and a locked door to the control room. 

Security tends to emphasize rings of protection, meaning that, if possible, the most important or most vulnerable assets should be placed in the center of... 

To determine if the rings of protection are effective, security programs are generally evaluated through use of penetration tests in which the facility people play the role of an attacker to see if the barriers work as expected. 

Selective reduction of a benzene ring (W. Grimme, 1970) or a C C double bond (J.E. Cole, 1962) in the presence of protected carbonyl groups (acetals or enol ethers) has been achieved by Birch reduction. Selective reduction of the C—C double bond of an a,ft-unsaturated ketone in the presence of a benzene ring is also possible in aprotic solution, because the benzene ring is redueed only very slowly in the absence of a proton donor (D. Caine, 1976). 

Eunctional or hard chromium plating (169,175) is a successfljl way of protecting a variety of industrial devices from wear and friction. The most important examples are cylinder liners and piston rings for internal combustion engines. Eunctional chromium deposits must be appHed to hard substrates, such as steel, and are appHed in a wide variety of thicknesses ranging from 2.5 to 500 ]Am. 

Tn general. Nelson and Schut s procedure is recommended for expansion of an unsymmetrically substituted cyclohexanone (for example, the A ring of a steroid 3-ketone). The yield is satisfactory in most instances and the precursors are readily available. However, the relative proportions of the two possible ketones may change as substituents are varied. The procedure is applicable to systems with additional ketones protected as ketals, double bonds, ethers and hydroxyl groups. 

Intermediate 8, the projected electrophile in a coupling reaction with intermediate 7, could conceivably be derived from iodolactone 16. In the synthetic direction, cleavage of the acetonide protecting group in 16 with concomitant intramolecular etherification could result in the formation of the functionalized tetrahydrofuran ring of... 

A 11011-addition procedure based on a tandem retroaldol/epoxide-opening/cycli-zation sequence has been utilized for the elaboration of the dihydrofuran ring of the reduced furanochroman subunit of phomactin A. The strategy utilizes the O-TBS-protected 3-epoxy-(3 -hydroxy ketone 201. Cleavage with TBAF starts the retro-... 

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