A Survey of Virtual Machine Migration Techniques in Cloud Computing

Cloud computing is an emerging computing technology that maintains computational resources on large data centers and accessed through internet, rather than on local computers. VM migration provides the capability to balance the load, system maintenance, etc. Virtualization technology gives power to cloud computing. The virtual machine migration techniques can be divided into two categories that is pre-copy and post-copy approach. The process to move running applications or VMs from one physical machine to another, is known as VM migration. In migration process the processor state, storage, memory and network connection are moved from one host to another.. Two important performance metrics are downtime and total migration time that the users care about most, because these metrics deals with service degradation and the time during which the service is unavailable. This paper focus on the analysis of live VM migration Techniques in cloud computing. Keywords: Cloud Computing, Virtualization, Virtual Machine, Live Virtual Machine Migration.

Linkage and FF-Regularity of Determinantal Rings

In this paper, we prove that the generic link of a generic determinantal ring defined by maximal minors is $F$-regular. In the process, we strengthen a result of Chardin and Ulrich. They showed that the generic residual intersections of a complete intersection ring with rational singularities again have rational singularities. We show that they are, in fact, $F$-regular in positive prime characteristic. Hochster and Huneke showed that generic determinantal rings are $F$-regular; however, their proof is quite involved. Our techniques allow us to give a new and simple proof of the $F$-regularity of generic determinantal rings defined by maximal minors.Comment: 18 pages; minor corrections in some proofs, exposition improved. Comments welcome

A cross-sectional study on quality of life among acne vulgaris patients

Background: In India, prevalence data from dermatology clinic in a teaching hospital in Varanasi reported acne in 50.6% of boys and 38.13% of girls in the age group 12-17 years. Though it is considered to be merely a cosmetic problem, it is associated with considerable psychological impairment which is comparable with certain chronic diseases. Acne patients are prone to low self-esteem, low self-confidence and social dysfunction which may lead to anxiety, depression, obsessive compulsiveness and sometimes suicidal ideation. Acne affects the functional abilities of individuals and patients have higher rate of unemployment when compared to those without acne. Acne also may have negative impact on personal relationships, sports activities and employment opportunities in teens and young adults. The management of acne must take into account the impact of acne on the patient’s quality of life. So the present study was carried out to determine the impact of acne and its clinical severity on quality of life among patients of different grades of acne patients in various age groups.Methods: The current cross sectional study was conducted in Patients diagnosed as acne vulgaris attending OPD of PCMS and RC Bhopal (India) in department of dermatology for a period of 2 year. (November 2012 – October 2014). 300 patients attending the Dermatology OPD with diagnosis of acne vulgaris were taken for the study. Patients aged 16 -35 years were included in our study. A detailed history was taken after obtaining consent from all the participants of study. Cardiff Acne disability index (CADI) and Dermatology life quality index (DLQI) were administered on patients to determine the impact of acne vulgaris on quality of life (QOL). Data was analyzed to compare the quality of life indices (CADI and DLQI) for duration and severity of acne.Results: Mean age of study population was 20.69 years. There was a male preponderance with ratio of 1.04:1 (M:F). According to this study 49% of patients had acne vulgaris for less than 1year. In present study maximum number 63.7% of patients presented with lesions over face followed by 14.7% of patients having lesions over face and back. According to DLQI scores of acne showed no effect in 4.3% of the patients, small effect in 26.3% of the patients, moderate effect in 38.7% of patients, very large effect in 29% of patients and extremely large effects on 1.7% of patients. According to CADI scores of acne showed low effect in 31.3% of the patients, majority had medium effect in 56.7% of patients and high effect was seen on 12 % of patients.Conclusions: Overall our study showed that quality of life is significantly impaired in patients of severe acne vulgaris. Use of these simple QOL measures as a part of integral clinical strategy will improve the outcome

When are the natural embeddings of classical invariant rings pure?

Consider a reductive linear algebraic group $G$ acting linearly on a polynomial ring $S$ over an infinite field; key examples are the general linear group, the symplectic group, the orthogonal group, and the special linear group, with the classical representations as in Weyl's book: for the general linear group, consider a direct sum of copies of the standard representation and copies of the dual; in the other cases take copies of the standard representation. The invariant rings in the respective cases are determinantal rings, rings defined by Pfaffians of alternating matrices, symmetric determinantal rings, and the Pl\"ucker coordinate rings of Grassmannians; these are the classical invariant rings of the title, with $S^G\subseteq S$ being the natural embedding. Over a field of characteristic zero, a reductive group is linearly reductive, and it follows that the invariant ring $S^G$ is a pure subring of $S$, equivalently, $S^G$ is a direct summand of $S$ as an $S^G$-module. Over fields of positive characteristic, reductive groups are typically no longer linearly reductive. We determine, in the positive characteristic case, precisely when the inclusion $S^G\subseteq S$ is pure. It turns out that if $S^G\subseteq S$ is pure, then either the invariant ring $S^G$ is regular, or the group $G$ is linearly reductive.Comment: 40 pages; comments welcome! Corrected references for the orthogonal group in characteristic two; results and proofs remain the sam