Improving the Performance of Deduplication-Based Backup Systems via Container Utilization Based Hot Fingerprint Entry Distilling

Data deduplication techniques construct an index consisting of fingerprint entries to identify and eliminate duplicated copies of repeating data. The bottleneck of disk-based index lookup and data fragmentation caused by eliminating duplicated chunks are two challenging issues in data deduplication. Deduplication-based backup systems generally employ containers storing contiguous chunks together with their fingerprints to preserve data locality for alleviating the two issues, which is still inadequate. To address these two issues, we propose a container utilization based hot fingerprint entry distilling strategy to improve the performance of deduplication-based backup systems. We divide the index into three parts: hot fingerprint entries, fragmented fingerprint entries, and useless fingerprint entries. A container with utilization smaller than a given threshold is called a sparse container . Fingerprint entries that point to non-sparse containers are hot fingerprint entries. For the remaining fingerprint entries, if a fingerprint entry matches any fingerprint of forthcoming backup chunks, it is classified as a fragmented fingerprint entry. Otherwise, it is classified as a useless fingerprint entry. We observe that hot fingerprint entries account for a small part of the index, whereas the remaining fingerprint entries account for the majority of the index. This intriguing observation inspires us to develop a hot fingerprint entry distilling approach named HID . HID segregates useless fingerprint entries from the index to improve memory utilization and bypass disk accesses. In addition, HID separates fragmented fingerprint entries to make a deduplication-based backup system directly rewrite fragmented chunks, thereby alleviating adverse fragmentation. Moreover, HID introduces a feature to treat fragmented chunks as unique chunks. This feature compensates for the shortcoming that a Bloom filter cannot directly identify certain duplicated chunks (i.e., the fragmented chunks). To take full advantage of the preceding feature, we propose an evolved HID strategy called EHID . EHID incorporates a Bloom filter, to which only hot fingerprints are mapped. In doing so, EHID exhibits two salient features: (i) EHID avoids disk accesses to identify unique chunks and the fragmented chunks; (ii) EHID slashes the false positive rate of the integrated Bloom filter. These salient features push EHID into the high-efficiency mode. Our experimental results show our approach reduces the average memory overhead of the index by 34.11% and 25.13% when using the Linux dataset and the FSL dataset, respectively. Furthermore, compared with the state-of-the-art method HAR, EHID boosts the average backup throughput by up to a factor of 2.25 with the Linux dataset, and EHID reduces the average disk I/O traffic by up to 66.21% when it comes to the FSL dataset. EHID also marginally improves the system's restore performance.

Probabilistic Method for Estimating the Level of Reliability of Solar Photovoltaic Systems for Households in Ghana

Renewable Energy Resources have been identified among the most promising sources of harnessing power for industrial and household consumption but their power generations highly uctuate so building renewable power systems without critical reliability analysis might result in frequent blackouts in the power system. Therefore, in this paper, a robust, effective and ecient design approach is proposed to handle the reliability issues. The study involves a Mathematical modelling strategy of the PV system to estimate the total PV power produced and the Bottom-Up approach for predicting the household load demand. The reliability is defined in terms of Loss of Load Probability. The design methodology was validated with a University Household. The data used for the analysis consists of daily average global solar irradiance and load profiles. The results revealed that throughout the year, November-February is where the system seems to be more reliable. Also, the results indicated that without buck-up systems, the system would experience an average annual power loss of 17.8753% and thus, it is recommended that either solar batteries or the grid are used as backup system to achieve a complete level of reliability.

REVOLUSI DIGITAL & DINAMIKA PERKEMBANGAN CRYPTOCURRENCY DITINJAU DARI PERSPEKTIF LITERATUR REVIEW

The spread of digital technology currently faster and influence on all of human dimension, including to the financial sector. The presence of cryptocurrency using blockchain technology has changed the previously system that has been used for a long period and it come a pros and cons. The system built using peer-to-peer cause the system no longer need the 3rd party that control the financial system and since the system decentralized. The nature of cryptocurrency which made as the same with gold characteristic such as the limitation of quantity, process to get it must through the mining process, more resistance from inflation are making people and society interested and significantly increase time by time. The decentralized and anonymous blockchain working system for token holders and safe has presented as a new paradigm in the financial sector. But on other hand, there are many challenges and dynamics that arise due to the emergence of these cryptocurrency, one of which is risk from the legal perspective where there are cases of money laundering involving of crypto, losses to the investor asset due to ICO process that not run smoothly, the emergence losses from crypto exchanges that hacked due to not have a high security backup system that made the customer losses their digital wallet. Crypto value that tend to have high volatility and fluctuating rates with fast count also increase the risk. The readiness of countries and drafting laws related to the crypto was contribution for this research. One of the biggest interested from the public is the use of crypto as long asset investment, where the values increasing from year to year, even Bitcoin as one of the cryptocurrencies that previously worthless but currently has very fantastic values and become a favourite from the investor

Home-Microgrid Energy Management Strategy Considering EV’s Participation in DR

Electric vehicles (EVs) have a lot of potential to play an essential role in the smart power grid. EVs not only can reduce the amount of emission yielded from fossil fuels but also can be considered as an energy storage system (ES) and a backup system. EVs could support the demand response (DR) strategy that is considered as utmost importance to shift electricity demand in peak hours. This article aims to assess the impact of the presence of EV on DR strategy in a home-microgrid (H-MG). In order to reach the optimal set point, our energy management system (EMS) has been merged with differential evolution (DE) method. The results were auspicious and showed that the proposed method could decrease market clearing price (MCP) by 26% and increase the performance of DR by 17%.

The Economics of Female Piety in Early Sufism

This paper examines the economics of female piety between the third/ninth and sixth/twelfth centuries. It traces Sufi approaches to poverty and working for a living (kasb) as well as kasb’s intersection with marriage and women. Rereading Sufi and non-Sufi biographies and historiographies reveals that there were wealthy women who initiated marriage with renowned Sufis to gain spiritual blessings, and others who financially supported their husbands. While the piety of male Sufis was usually asserted through material poverty, the piety of female mystics was asserted through wealth and almsgiving. This paper examines this piety through different female kinships—whether mothers, wives or sisters. Similar to the spousal support of wives for their husbands, sisters very often acted as an impressive backup system for their Sufi brothers. Mothers, however, effected a great socio-religious impact through the cherished principles of a mother’s right to control her son and a son’s duty to venerate his mother. This devotion was often constraining financially and Sufis needed to pay attention to the financial implications while still pursuing progress on the Sufi path.

State-space Construction of Hybrid Petri Nets with Multiple Stochastic Firings

Hybrid Petri nets have been extended to include general transitions that fire after a randomly distributed amount of time. With a single general one-shot transition the state space and evolution over time can be represented either as a Parametric Location Tree or as a Stochastic Time Diagram . Recent work has shown that both representations can be combined and then allow multiple stochastic firings. This work presents an algorithm for building the Parametric Location Tree with multiple general transition firings and shows how its transient probability distribution can be computed using multi-dimensional integration. We discuss the (dis-)advantages of an interval arithmetic and a geometric approach to compute the areas of integration. Furthermore, we provide details on how to perform a Monte Carlo integration either directly on these intervals or convex polytopes, or after transformation to standard simplices. A case study on a battery-backup system shows the feasibility of the approach and discusses the performance of the different integration approaches.

Performance Evaluation of 780 Wp Rooftop Solar PV Power Backup System in Western Kenya

Aim: This study aimed to carry out performance analysis of a 780 Wp PV power backup system installed at a learning institution in Western. Study design: To achieve this goal, site solar radiation received, ambient temperatures, dc current and dc voltages were measured in order to carry out performance evaluation of the PV backup system. Place and Duration of Study: Department of electronics and electrical, Kaiboi Technical Training Institute in Nandi County, western Kenya was studied, between January 2020 and December 2020. Methodology: Performance of any PV system depends on the operating conditions (solar radiation, ambient/module temperature, etc.) available at the site (geolocation dependent), installation (tilt and orientation) of the arrays, and finally proper system sizing (PV array, battery, BOS). In this paper, standard performance parameters reported in literature were utilized to evaluate the performance of the studied PV backup system. The array comprises of four panels interconnected in series/parallel to produce an output power rating of 780 W. A Pyranometer was mounted on the plane of array (POA) to measure solar radiation intercepted by the PV array where daily data were acquired at an interval of five minutes. I-v data were also recorded. Different literature was reviewed to identify the way to do this work. Results: Based on the performance of the studied PV system, results obtained show that annual effective energy output is 3412.94 kWh, array efficiency range between 11.6% to 14.1% depending on amount of solar radiation, array yield of 4.88 kWh/kW, reference yield of 5.5 kWh/kW, annual average performance ratio of 76.3% and average array capture losses of 0.52 kWh/kW. Conclusion: It found that the PV backup system need ~5-6 hours to operate at the array’s rated output power, and that the PV backup system performance is adequate with regard to yield and performance ratios.

Microgrid system including PV generation and hybrid backup system

This Master’s thesis project introduces a micro-grid system that includes a hybrid power storage backup system and photovoltaic module power generation system, which is connected to the grid and supports the hybrid backup system. The first section presents a solution or algorithm to an existing problem in an energy flow management strategy for the hybrid energy storage system. In the second section, power is provided from the photovoltaic arrays by the convenience of the Maximum Power Point Tracking (MPPT) for each photovoltaic module. The generated power will charge the storage backup system. The micro-grid is capable of selling the surplus power to the utility grid. A master controller optimizes integration, dispatching and control over the whole micro-grid operation. There have been many different control strategies and topologies presented over the years to manage the energy flow for hybrid energy storage systems; however, there are some aspects that differentiate some from others, such as real-time prediction, cumbersome architecture, full spectrum control over recourses, and cost-effectiveness. The first section of this thesis proposes a control strategy on hybrid energy storage systems based on fundamental electrical principles. The low volume and simple algorithm make the controller easy to perform on the embedded systems and quickly responds within a tiny space. The control strategy is equipped with a load prediction method, which provides a fast response at the time of load current surge. The controller architect provides the full control over all the resources. The presented controller is cost-effective by increasing the battery life and by minimizing the power loss in the hybrid storage backup system. The simulation results in two different experiments validate the efficiency and performance of the offered control strategy for hybrid backup system.