Security in Peer-to-Peer SIP VoIP

VoIP (Voice over Internet Protocol) is one of the fastest growing technologies in the world. It is used by people all over the world for communication. But with the growing popularity of internet, security is one of the biggest concerns. It is important that the intruders are not able to sniff the packets that are transmitted over the internet through VoIP. Session Initiation Protocol (SIP) is the most popular and commonly used protocol of VoIP. Now days, companies like Skype are using Peer-to-Peer SIP VoIP for faster and better performance. Through this project I am improving an already existing Peer-to-Peer SIP VoIP called SOSIMPLE P2P VoIP by adding confidentiality in the protocol with the help of public key cryptography

FINITE ELEMENT ANALYSIS FOR OPTIMIZING ANTENNA FOR MICROWAVE COAGULATION THERAPY

Microwave coagulation therapy (MCT) is emerging as an attractive modality for thermal therapy of soft tissues targeted in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. In this field of microwave coagulation therapy, the use of minimally invasive antenna is recognized as a very promising technique for the treatment of small tumors because a very thin antenna can be easily inserted inside the body and precisely localized using the advanced 3D imaging techniques and surgical robots. The authors investigated the microwave coaxial antenna operating at 2.45 GHz by varying the slots size for the removal of liver tumor. The analysis was done using 2D finite element modeling. By several optimization steps the antenna is simulated and optimized by comparing the values of specific absorption rate (SAR), mesh statistics and temperature distributions in tissue generated by the antenna with the variations of dimensions of slot from 1 mm to 1.7 mm

Cannabis use and hypomania in young people: a prospective analysis

Background: Cannabis use in young people is common and associated with psychiatric disorders. However, the prospective link between cannabis use and bipolar disorder symptoms has rarely been investigated. The study hypothesis was that adolescent cannabis use is associated with hypomania in early adulthood via several potential etiological pathways. Methods: Data were used from the Avon Longitudinal Study of Parents and Children, a UK birth cohort study. The prospective link between cannabis use at age 17 and hypomania at age 22–23 years was tested using regression analysis, adjusted for gender, early environmental risk factors, alcohol and drug use, and depression and psychotic symptoms at age 18 years. Path analysis examined direct and indirect effects of the link and whether gender, childhood family adversity, or childhood abuse are associated with hypomania via an increased risk of cannabis use. Results: Data were available on 3370 participants. Cannabis use at least 2–3 times weekly was associated with later hypomania (OR = 2.21, 95% CI = 1.49–3.28) after adjustment. There was a dose–response relationship (any use vs weekly). Cannabis use mediated the association of both childhood sexual abuse and hypomania, and male gender and hypomania. The cannabis use-hypomania link was not mediated by depression or psychotic symptoms. Conclusions: Adolescent cannabis use may be an independent risk factor for future hypomania, and the nature of the association suggests a potential causal link. Cannabis use mediates the link between childhood abuse and future hypomania. As such it might be a useful target for indicated prevention of hypomania

A useful inequality of inverse hyperbolic tangent

We prove an inequality related to arctanh, resolving a conjecture of Gu and Polyanskiy [arXiv:2303.14689].Comment: 3 page

Decomposability and structure of nonnegative bands in ℳn(ℝ)

AbstractA standard subspace of ℝn is a space spanned by a subset of the standard basis {e1, e2,…,en}. A multiplicative semigroup. ℒ in ℳn(ℝ) is said to be decomposable if its members have a common nontrivial standard invariant subspace. Necessary and sufficient conditions for decomposability of nonnegative semigroups are given. In particular, decomposability of nonnegative bands (semigroups of idempotents) and their structure is discussed. It is proved that a nonnegative band with each member having rank greater than 1 is decomposable. Also, a geometric characterization of maximal, rank-one nonnegative bands is given

Host-parasite interactions between freshwater pearl mussels (Margaritifera margaritifera) and their salmonid hosts

The freshwater pearl mussel, Margaritifera margaritifera, is an endangered bivalve which has suffered a serious decline across its Holarctic distribution. It has a complex life cycle which involves an obligate parasitic stage on a suitable host. M. margaritifera populations are very host specific, and they are able to metamorphose only on the gills of Atlantic salmon (Salmo salar), sea trout (Salmo trutta f. trutta) or brown trout (S. trutta f. fario). Currently, the main concern is the lack of juvenile recruitment and survival in organically enriched river sediments. Consequently, several conservation programmes are rearing mussels in hatcheries, for eventual release back into their natural habitat when they are older and better able to survive. Although M. margaritifera do not reproduce on their hosts, their survival is highly dependent on the presence of suitable hosts. The main purpose of this study was to improve our understanding of the host-parasite interactions and their influence on glochidial or juvenile mussel fitness, with the aim of providing information that could be used to refine future conservation strategies. In the first experiment, the duration of the parasitic phase had a significant positive influence on post parasitic fitness of juvenile mussels in eight populations in Norway. Fitness was measured as size at excystment, post parasitic growth and survival. The strong positive relationship observed between the test variables clearly indicated that glochidial growth and development were dependent on individual host-parasite compatibility. In the same experiment, temperature was also observed to be an important factor governing excystment of juvenile mussels, with higher temperatures decreasing the duration of the parasitic phase. The variation in host suitability has been linked to environmental conditions, host age and/or size, genetic composition of the host and parasite, or a combination of these factors. Therefore, in the second experiment, the effect of host age on glochidial infestation was examined under common garden conditions. Hosts (0+ and 1+) were infested with glochidia from closely related mothers in order to remove the confounding effects of genotype-specific host interactions. A host age dependent immune response was observed, i.e. the 0+ hosts displayed a resistant strategy, whereas the 1+ hosts displayed a tolerant one. In the second and third experiments, the virulent effects of glochidia on their hosts were examined, and measured as haematocrit values and host mortality respectively. Haematocrit values were significantly elevated in heavily infested hosts, which indicated respiratory distress (Chapter 3). In addition, glochidia were highly virulent on the less suitable host species, resulting in high mortalities of infested hosts (Chapter 4). Both these results display the parasitic nature of M. margaritifera in the host-parasite interaction. In the third experiment, the hypothesis that glochidia from a single mother could infest both salmon and trout hosts was examined. The results showed that glochidia from a population that uses salmon as its principal host were able to infest both species, but some mothers displayed a bias for either salmon or trout. These observations were probably a result of the higher genetic diversity observed in salmon-mussel populations. Individual and population level genetic diversity is associated with species fitness and an ability to adapt to a changing environment, which can help ensure long-term survival. All the results of this study clearly indicate that the degree of host-parasite compatibility has an influence on glochidial and juvenile mussel fitness. Further studies should investigate factors that influence host-parasite interactions, for example the diversity of the genes of the host major histocompatibility complex (MHC). Based on the results, it is recommended that naive 1+ hosts are preferably used in captive breeding programmes, as this will maximise the production of juvenile mussels. The use of high quality hosts will also minimise the possible selection and genetic drift effects. Such effects lead to a deterioration in the evolutionary potential to adapt to a changing environment. Since glochidial development and successful metamorphosis into juvenile mussels is highly dependent on good host condition and survival, it is recommended that conservation efforts should focus on methods that can guarantee this

Objective Measurement of Speech Quality in VoIP over Wireless LAN during Handoff

Quality of Service is a very important factor to determine the quality of a VoIP call. Different subjective and objective models exist for evaluating the speech quality in VoIP. E-model is one of the objective methods of measuring the speech quality; it considers various factors like packet loss, delay and codec impairments. The calculations of Emodel are not very accurate in case of handovers – when a VoIP call moves from one wireless LAN to another. This project conducted experimental evaluation of performance of E-model during handovers and proposes a new approach to accurately calculate the speech quality of VoIP during handovers. A detailed description of the experimental setup and the comparison of the new approach with E-model is presented in this report

The Indian Premier League: What are the factors that determine player value?

This paper examines and tries to estimate the importance of various characteristics that go into attributing specific dollar values to cricketers. The auction process employed in the Indian Premier League enables one to associate players with specific monetary values and this paper uses various performance criteria to assess what the key variables are towards creating a highly valued cricket player. This paper finds that various batting statistics are of significance in addition to the age and nationality of players