فهرست مطالب a. sahafi

Blockchain technology as a distributed and tamper-proof data ledger is attracting more and more attention from various fields around the world. Due to the continuously growing of the blockchain in both transaction data and the number of nodes joining the network, scalability emerges as a challenging issue.

In this survey, the existing scalability solutions in the blockchain are discussed under five categories including on-chain scalability, off-chain scalability, scalable consensus mechanisms, DAG-based scalability, and horizontal scalability through sharding. Meanwhile, the novelties they have created on the fundamental layers of the blockchain architecture are investigated.

As a result, the advantages and disadvantages of the discussed mechanisms are pointed out, and a comparison between them in terms of different scalability metrics such as throughput, latency, bandwidth, and storage usage is presented. Therefore, this study provides a comprehensive understanding of the various aspects of blockchain scalability and the available scalability solutions. Finally, the research directions and open issues in each category are argued to motivate further improvement efforts for blockchain scalability in the future.

Scalability allows blockchain system to sustain its performance as it grows up. Lack of scalability has a negative effect on the mass adoption of the blockchain in practical environments. This paper presents a profound analysis of the existing scalability solutions, the issues and challenges they address, and the ones that are not resolved yet. Consequently, it inspires novel ideas for more scalable and efficient blockchains in the future.

Today, the increased number of Internet-connected smart devices require powerful computer processing servers such as cloud and fog and necessitate fulfilling requests and services more than ever before. The geographical distance of IoT devices to fog and cloud servers have turned issues such as delay and energy consumption into major challenges. However, fog computing technology has emerged as a promising technology in this field.

In this paper, service/energy management approaches are generally surveyed. Then, we explain our motivation for the systematic literature review procedure (SLR) and how to select the related works.

This paper introduces four domains of service management and energy management, including Architecture, Resource Management, Scheduling management, and Service Management. Scheduling management has been used in 38% of the papers. Therefore, they have the highest service management and energy management. Also, Resource Management is the second domain that has been able to attract about 26% of the papers in service management and energy management.

About 81% of the fog computing papers simulated their approaches, and the others implemented their schemes using a testbed in the real environment. Furthermore, 30% of the papers presented an architecture or framework for their research, along with their research. In this systematic literature review, papers have been extracted from five valid databases, including IEEE Xplore, Wiley, Science Direct (Elsevier), Springer Link, and Taylor & Francis, from 2013 to 2022. We obtained 1596 papers related to the discussed subject. We filtered them and achieved 47 distinct studies. In the following, we analyze and discuss these studies; then we review the parameters of service quality in the papers, and ultimately, we present the benefits, drawbacks, and innovations of each study.

The aim of this study was to evaluate the effect of Heatsynch and Ovsynch(two methods of ovulation synchronization) on pregnancy rate in dairy cows. This study was carried out in a large dairy herd in suburbs of Esfehan province. In total 113 dairy cows with 50-200 days in milk entered in the study. In this experiment cows were alternately assigned to three proups.1) control group (n=50) received no treatment. Cows that were detected in estrous were inseminated by on farm technician.2) Ovsynch group (n=46) received an i.m injection of 10 μg GnRH analog on days 0 and 9 and an i.m injection of 500 μg of PGF2α on day 7, then inseminated 16-20 hour after second GnRH injection. 3) Heatsynch group (n=37) received an i.m injection of 10 μg GnRH analog and 500 μg of PGF2α on days 0 and 7 respectively and then then 1mg estradiol cypiyonate 24 hour after PG injection. Cows that were detected in estrous after estradiol treatment were inseminated as a.m. / p.m.protocol. Timed artificial insemination(TAI) was performed for cows that were not detected in estrous 48 hourafter estradiol treatment.Pregnancy detection were performed on day 30 and between days 40-45 after insemination by ultrasonography and rectal palpation respectively. The differences in Conception rate between three groups were analyzed by using Chi-Square method. Although conception rate in Ovsynchgroup (%41.3) were higher than Heatsynch(%37.8) and control(%36) groups, but there was no significant differences in conception rate between three groups.