A statistical and distributed packet filter against DDoS attacks in Cloud environment

Distributed Denial of Service (DDoS) attacks are a serious threat to Cloud. These attacks consume large amount of resources and increase the service usage cost by a significant factor. Due to multi-tenancy and self-provisioning properties of Cloud, traditional DDoS detection techniques cannot be directly applied. Hence, there is a need for Cloud-specific DDoS detection framework. In this paper, a statistical and distributed network packet filtering model is proposed against DDoS attacks in Cloud. The key idea of this scheme is to distribute multiple packet filters among individual virtual machines, which generate and share collective profile of normal behaviour with a coordinator node at constant intervals. Statistics of selected network attributes construct the normal behaviour profile. Based on the deviation from normal behaviour a decision is made whether to accept or reject the incoming packet. The coordinator node monitors filter and distribute the averaged profile to newly provisioned nodes. Individual profiles have low memory and storage requirements and are updated dynamically. Simulation study indicates the effectiveness of this scheme in detecting DDoS attacks in Cloud.     

RETENTION AND BIOACCESSIBILITY OF β‐CAROTENE FROM NATURAL AND SYNTHETIC SOURCES ON BAKING

ABSTRACT

The investigation aimed at determining the retention and bioaccessibility of β‐carotene on baking. Bun was formulated incorporating dehydrated carrot/drumstick leaves/synthetic form of β‐carotene at acceptable levels. The effect of citric acid and turmeric powder on the bioaccessibility of β‐carotene was examined. Buns were analyzed for proximate composition, total and bioaccessible β‐carotene. Incorporation of different sources of β‐carotene did not alter the physical characteristics and proximate composition of the buns. Retention of β‐carotene on baking ranged between 62 and 72% in buns with natural sources and 35% in buns with synthetic source. β‐carotene in the buns showed a high degree of stability on storage. Bioaccessibility of β‐carotene in bun was 5.8% with carrot, 7.1% with synthetic source and below 1% with drumstick leaves. Addition of enhancing components increased the bioaccessibility to a remarkable extent. The study results suggest the possibility of fortifying buns with β‐carotene with enhanced bioaccessibility.

PRACTICAL APPLICATIONS

The study identified natural and synthetic forms of β‐carotene to be incorporated in bun. Bun is the ideal product for fortification; it is easily acceptable by children in whom vitamin A deficiency is highly prevalent. Carrot and drumstick leaves are rich and economical sources of β‐carotene. The selected vegetable sources contain other micronutrients in addition to β‐carotene that will improve the nutritive value of buns. Hence, incorporation of carrot and drumstick leaves in buns will have good market potential. The selected sources of β‐carotene are from easily available natural sources which are economically feasible. The product formulation is well standardized for organoleptic parameters for large‐scale production.