SS6: Online Short-Code RAID-6 Scaling by Optimizing New Disk Location and Data Migration

Thanks to excellent reliability, availability, flexibility and scalability, redundant arrays of independent (or inexpensive) disks (RAID) are widely deployed in large-scale data centers. RAID scaling effectively relieves the storage pressure of the data center and increases both the capacity and I/O parallelism of storage systems. To regain load balancing among all disks including old and new, some data usually are migrated from old disks to new disks. Owing to unique parity layouts of erasure codes, traditional scaling approaches may incur high migration overhead on RAID-6 scaling. This paper proposes an efficient approach based Short-Code for RAID-6 scaling. The approach exhibits three salient features: first, SS6 introduces $\tau $ to determine where new disks should be inserted. Second, SS6 minimizes migration overhead by delineating migration areas. Third, SS6 reduces the XOR calculation cost by optimizing parity update. The numerical results and experiment results demonstrate that (i) SS6 reduces the amount of data migration and improves the scaling performance compared with Round-Robin and Semi-RR under offline, (ii) SS6 decreases the total scaling time against Round-Robin and Semi-RR under two real-world I/O workloads (iii) the user average response time of SS6 is better than the other two approaches during scaling and after scaling.

Optimised URL Shortener using Cloud Platform

Short URLs have become commonplace. Short URLs, which are especially popular in social networking services, have witnessed a significant increase in their use in recent years, largely due to Twitter's restriction on message length to 140 characters. We рrоvidе a first сhаrасterizаtiоn in the usage of short URLs in this рарer. Our specific goal is to create a system architecture for short URLs and have an optimized solution of how to use them and as well as their potential impact on web performance. Our project is made while keeping in mind that the generated URL has to be one third the size of a given url. This allows the user the functionality to share the URL with multiple individuals. Our system also incorporates the idea of tracking each individual shortened URL by the usage of a short code. It gives the user the control over their generated URLs.

New encoding/decoding design of SAC-OCDMA system with fixed correlation zone code

The short code length makes impossible to increases the number of users in the SAC-OCDMA system, this work proposed a new family code with a fixed correlation zone, which makes it possible to construct w different zones for the code, every zone has a fixed correlation value, where the correlation by zone is from 0 to w-1, w is the code weight, i.e., this code is characterized by the incremented cross-correlation value between every two successive zones, The obtained results demonstrate that the proposed code provides better performances compared to other codes.

Performances of BICM-ID system using CRSC code in optical transmissions

Recently, using iterative decoding algorithms to achieve an interesting bit error rate for spectrally efficient modulation become a necessity for optical transmission, in this paper, we propose a coded modulation scheme based on bit interleaving circular recursive systematic convolutional (CRSC) code and 16-QAM modulation. The proposal system considered as a serial concatenation of a channel encoder, a bit interleaver and M-ary modulator can be flexible easy to implement using a short code length. For a spectral efficiency $\eta =3\text{bit}/s/Hz$, the coding gain at a bit error rate of 10−6 is about 8 dB.

The Effect of Women’s Differential Access to Messages on Their Adoption of Mobile Health Services and Pregnancy Behavior in Bangladesh: Retrospective Cross-Sectional Study

Background Text or voice messages have been used as a popular method for improving women’s knowledge on birth preparedness and newborn health care practices worldwide. The Aponjon service in Bangladesh provides twice-weekly messages to female subscribers about their pregnancy and newborn care on mobile phones that they own or share with family members. It is important to understand whether women’s singular access to a phone affects their service satisfaction and the adoption of health messages before deploying such interventions in resource-limited settings. Objective This study aims to evaluate the effect of women’s singular and shared access to mobile phone messages on their service utilization and perceived behavioral change around birth preparedness and pregnancy care. Methods In 2014, Aponjon conducted a retrospective cross-sectional survey of 459 female subscribers who received text or voice messages during their pregnancy by themselves (n=253) or with family members (n=206). We performed multivariable regression analyses to investigate the association between pregnant women’s differential access to messages and other socioeconomic factors and outcomes of service satisfaction, ability to recall service short code, ability to identify danger signs of pregnancy, preference for skilled delivery, arrangement of a blood donor for delivery and pregnancy complications, maternal nutrition, use of potable drinking water, and washing hands with soap for hygiene. Results In the multivariable analysis, women who had singular access to messages had higher odds of reporting high satisfaction (odds ratio [OR] 1.72, 95% CI 1.12-2.63; P=.01), recalling the service short code (OR 2.88, 95% CI 1.90-4.36; P<.001), consuming nutritious food 5 times a day (OR 1.58, 95% CI 1.04-2.40; P=.03), and following the instructions of Aponjon on drinking potable water (OR 1.90, 95% CI 1.17-3.09; P=.01) than women who shared access with family members. Women’s differential access to messages did not affect their knowledge of danger signs and preparedness around delivery. Adolescent women and women aged 20-24 years had lower odds of planning safe deliveries than older women (aged≥25 years). Secondary education was statistically significantly associated with women’s ability to recall the short code and pregnancy danger signs, plan safe delivery, and select blood donors for emergencies. Higher family income was associated with women’s satisfaction, recognition of danger signs, and arrangement of blood donors and nutritious diet. Women who received more than 4 antenatal care visits had higher odds of liking the service, preferring skilled delivery, recalling danger signs, and consuming nutritious food. Conclusions The capacity of women to independently access mobile phone messages can improve their adoption of mobile health services and some pregnancy health care practices. A holistic approach and equitable support are required to improve access to resources and knowledge of delivery preparedness among low-literate and younger women in low-income households.