Performance modelling with adaptive hidden Markov models and discriminatory processor sharing queues

In modern computer systems, workload varies at different times and locations. It is important to model the performance of such systems via workload models that are both representative and efficient. For example, model-generated workloads represent realistic system behaviour, especially during peak times, when it is crucial to predict and address performance bottlenecks. In this thesis, we model performance, namely throughput and delay, using adaptive models and discrete queues. Hidden Markov models (HMMs) parsimoniously capture the correlation and burstiness of workloads with spatiotemporal characteristics. By adapting the batch training of standard HMMs to incremental learning, online HMMs act as benchmarks on workloads obtained from live systems (i.e. storage systems and financial markets) and reduce time complexity of the Baum-Welch algorithm. Similarly, by extending HMM capabilities to train on multiple traces simultaneously it follows that workloads of different types are modelled in parallel by a multi-input HMM. Typically, the HMM-generated traces verify the throughput and burstiness of the real data. Applications of adaptive HMMs include predicting user behaviour in social networks and performance-energy measurements in smartphone applications. Equally important is measuring system delay through response times. For example, workloads such as Internet traffic arriving at routers are affected by queueing delays. To meet quality of service needs, queueing delays must be minimised and, hence, it is important to model and predict such queueing delays in an efficient and cost-effective manner. Therefore, we propose a class of discrete, processor-sharing queues for approximating queueing delay as response time distributions, which represent service level agreements at specific spatiotemporal levels. We adapt discrete queues to model job arrivals with distributions given by a Markov-modulated Poisson process (MMPP) and served under discriminatory processor-sharing scheduling. Further, we propose a dynamic strategy of service allocation to minimise delays in UDP traffic flows whilst maximising a utility function.Open Acces

CLADAG 2021 BOOK OF ABSTRACTS AND SHORT PAPERS

The book collects the short papers presented at the 13th Scientific Meeting of the Classification and Data Analysis Group (CLADAG) of the Italian Statistical Society (SIS). The meeting has been organized by the Department of Statistics, Computer Science and Applications of the University of Florence, under the auspices of the Italian Statistical Society and the International Federation of Classification Societies (IFCS). CLADAG is a member of the IFCS, a federation of national, regional, and linguistically-based classification societies. It is a non-profit, non-political scientific organization, whose aims are to further classification research

Evaluation of glottal characteristics for speaker identification.

Based on the assumption that the physical characteristics of people's vocal apparatus cause their voices to have distinctive characteristics, this thesis reports on investigations into the use of the long-term average glottal response for speaker identification. The long-term average glottal response is a new feature that is obtained by overlaying successive vocal tract responses within an utterance. The way in which the long-term average glottal response varies with accent and gender is examined using a population of 352 American English speakers from eight different accent regions. Descriptors are defined that characterize the shape of the long-term average glottal response. Factor analysis of the descriptors of the long-term average glottal responses shows that the most important factor contains significant contributions from descriptors comprised of the coefficients of cubics fitted to the long-term average glottal response. Discriminant analysis demonstrates that the long-term average glottal response is potentially useful for classifying speakers according to their gender, but is not useful for distinguishing American accents. The identification accuracy of the long-term average glottal response is compared with that obtained from vocal tract features. Identification experiments are performed using a speaker database containing utterances from twenty speakers of the digits zero to nine. Vocal tract features, which consist of cepstral coefficients, partial correlation coefficients and linear prediction coefficients, are shown to be more accurate than the long-term average glottal response. Despite analysis of the training data indicating that the long-term average glottal response was uncorrelated with the vocal tract features, various feature combinations gave insignificant improvements in identification accuracy. The effect of noise and distortion on speaker identification is examined for each of the features. It is found that the identification performance of the long-term average glottal response is insensitive to noise compared with cepstral coefficients, partial correlation coefficients and the long-term average spectrum, but that it is highly sensitive to variations in the phase response of the speech transmission channel. Before reporting on the identification experiments, the thesis introduces speech production, speech models and background to the various features used in the experiments. Investigations into the long-term average glottal response demonstrate that it approximates the glottal pulse convolved with the long-term average impulse response, and this relationship is verified using synthetic speech. Furthermore, the spectrum of the long-term average glottal response extracted from pre-emphasized speech is shown to be similar to the long-term average spectrum of pre-emphasized speech, but computationally much simpler

WOFEX 2021 : 19th annual workshop, Ostrava, 1th September 2021 : proceedings of papers

The workshop WOFEX 2021 (PhD workshop of Faculty of Electrical Engineer-ing and Computer Science) was held on September 1st September 2021 at the VSB – Technical University of Ostrava. The workshop offers an opportunity for students to meet and share their research experiences, to discover commonalities in research and studentship, and to foster a collaborative environment for joint problem solving. PhD students are encouraged to attend in order to ensure a broad, unconfined discussion. In that view, this workshop is intended for students and researchers of this faculty offering opportunities to meet new colleagues.Ostrav

A Summary of the Naval Postgraduate School Research Program, 1986

This report contains 227 summaries of research projects which were carried out under funding to the Naval Postgraduate School Research Program. This research was conducted under the areas of Computer Science, Mathematics, Administrative Sciences, Operations Research, National Security Affairs, Physics, Electrical and Computer Engineering, Meteorology, Aeronautics, Oceanography, and Mechanical Engineering. The table of contents identifies specific research topics.Approved for public release; distribution is unlimited

Performance analysis for wireless G (IEEE 802.11G) and wireless N (IEEE 802.11N) in outdoor environment

This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. The comparison consider on coverage area (mobility), throughput and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g

Performance Analysis For Wireless G (IEEE 802.11 G) And Wireless N (IEEE 802.11 N) In Outdoor Environment

This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. the comparison consider on coverage area (mobility), through put and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g

Harnessing Chickpea Value Chain for Nutrition Security and Commercialization of Smallholder Agriculture in Africa

This proceedings on "Harnessing Chickpea Value Chain for Nutrition Security and Commercialization of Stallholder Agriculture in Africa’ is the outcome of the First International Chickpea Workshop held in Debre Zeit, Ethiopia – the location which represents the major chickpea growing areas in the country as well as Center of Excellence for the national chickpea research. As it is the first of its kind in that scope, the First International Chickpea Workshop created a vibrant interaction among our global partners and individuals from the chickpea communities. In looking forward, it has been strongly believed that the workshop not only documents what has been achieved by the different interaction levels but also demonstrates that the NARS could play significant role in promoting science and knowledge to resolve agricultural bottlenecks of their own. Accounting for ~2.5% of world and more than 55% of Africa's chickpea production, Ethiopia stands to the top 10 global chickpea producing countries while it is the 1st producer in Africa. Research advances in breeding and crop management practices over the four decades resulted in the development and release of proven technologies that brought a dramatic productivity increase from less than a tone to close to two tons in just a decade and half, comparable to many high input cereals, which has significantly improved the livelihoods of smallholder farmers. In addition, the crop has emerged as one of the major agricultural export commodities next to coffee, sesame and beans. As a result, Ethiopian chickpea has now been shifted from a simple precursor crop to a principal component of the cropping system that significantly contributed in leveraging poverty reduction..

Parental Awareness on Teenage Smoking Behavior in Yogyakarta and Bali

Smoking or being healthy is not a suitable offers to young teenagers (ages 13-15 years), because they have not able to take responsibility for the negative impacts of their choices on smoking behaviors. In addition, they have not been well informed about cigarettes and their dangers. The data indicate that there was a high rate of smoking behavior for adolescents aged 13-15 years (55.71%), including trial smoking behavior. However, only 39% of parents are aware of their children smoking behavior. This study aims were determining the awareness of parents and its form on the smoking behavior of their teenage children after treatment. The design of this study was a pre-posttest experiment with control group design. Around 301 parents of 8th grade boy student from 7 junior high schools were considered respondents. The latter came from 2 locations namely Yogyakarta and Tabanan Bali. For determining the respondents, cluster random sampling was used. The respondents were grouped into 3 groups (X1 treatment group, X2 treatment group and control group). The treatment is to provide information about cigarettes and its danger. It was given once by health workers. The measured variable is the respondent awareness and its form that was obtained from the students using selfreported questionnaire. Data were analyzed using Kruskal Wallis and Chi-square test with 0.05 level of significant. The results showed that there was a significant increase the parental awareness after treatment (p value 0.0001). This can happen because the intervention strengthened the predisposing factor to realize the respondents’ caring behavior as well as the concept of behavioral determinant of LW Green. In the X2 treatment group (non-smoker respondents) showed a higher increase of parental awareness than X1 treatment group (smoker respondents) and control group. This happens because they get support from health workers and get healthy conditions as resulted from their behavior. They will continue to remain as nonsmokers and encourage their teenage children to look up to them in order to get a similar reward, as the law of effect theory by E.L Thorndike made it clear. The form of awareness that many parents chose is the message upholding the primary prevention. The conclusion of the research stresses on continuously fetching more knowledge about cigarettes and its dangers, as one of the best mechanisms that can increase the parental awareness against teenage smoking behavior