A blockchain is a distributed, digitized and consensus-based secure information storage mechanism. The present article provides an overview of blockchain based e-voting systems. The primary purpose of this review is to study the up-to-date state of blockchain-based voting research along with associated possible challenges while aiming to forecast future directions. The methodology applied in the review is a systematic review approach. Following an introduction to the basic structure and features of the blockchain in relation to e-voting, we provide a conceptual description of the desired blockchain-based e-voting application. Symmetrical and asymmetrical cryptography improvements play a key role in developing blockchain systems. We have extracted and reviewed 63 research papers from scientific databases that have advised the adoption of the blockchain framework to voting systems. These articles indicate that blockchain-supported voting systems may provide different solutions than traditional e-voting. We classified the main prevailing issues into the five following categories: general, integrity, coin-based, privacy and consensus. As a result of this research, it was determined that blockchain systems can provide solutions to certain problems that prevail in current election systems. On the other hand, privacy protection and transaction speed are most frequently emphasized problems in blockchain applications. Security of remote participation and scalability should be improved for sustainable blockchain based e-voting. It was concluded that frameworks needed enhancements in order to be used in voting systems due to these reservations.

Blockchain technology is being used in many areas, during last few years. Furthermore, different application opportunities are still been investigated. Blockchain relies on and permits to implement the concept of Decentralized Application (DApps). This makes the applications more transparent, distributed and flexible. The complexity of blockchain and its integration problems require expertise that differs from traditional application development approaches. Within this context, this paper presents our experience in building a DApp with one of the most popular blockchain based platforms called Ethereum.

Security and trust are seen as the most important issues in electronic voting systems. Therefore, it is necessary to use cryptographic procedures to ensure anonymity, security, privacy, and reliability in these systems. In recent years, blockchain has become one of the most commonly used methods for securing data storage and transmission through decentralized applications. E-voting is one of these application areas. However, data manipulation is still seen as a major potential problem in e-voting systems. In theproposed model, administrators or miners are prevented from previewing election results which are normally accessible data due to the blockchain structure. A double-layer encryption model is proposed and tested to prevent manipulations that may occur with the election results. It is ensured that the election results can be counted after the participation of all stakeholders at the end. In this way, potential manipulations may be prevented during the election period. As a result of the model, the privacy of voters is ensured, no central authority is needed, and the recorded votes are kept in a distributed structure.

A smart contract is a concept of computer protocols that helps to facilitate blockchain technology. This blockchain-based smart contract is a public ledger of all participating transactions. It is considered a self-executable application and contains predetermined rules. It also operates by decentralizing networks that are shared between all parties, and this execution of contracts between parties could be securely done without a middleman or a third party. With blockchain technology, developers could provide an efficient framework and ensure security issues. While the new blockchain has successfully been developed to prevent the problems of fraud and hacking, there is still a considerable risk concerning security and confidentiality. Therefore, we should not underestimate this matter. This study aims to review the potential risks that may take place on blockchain-based smart contracts. In addition, the options that may assist application developers in order to provide viable guidance, and to avoiding these security vulnerabilities.

The scientific publishing industry is dominated by a few publishers that use centralized systems, which decrease the quality of studies and make the publication process longer. Traditional publication systems generally have high publication costs, slow and biased review processes, copyrights held by publishers, lack of rewards for contributors, lack of connection among researchers, etc. Accordingly, we propose a decentralized blockchain-based scientific publication platform to eliminate the traditional publication system deficiencies. The proposed system uses Ethereum smart contracts to accelerate the publication process and abate the biased evaluation process while reducing the publication cost. The proposed model also improves the quality of scientific studies by adding new features to the publication process. The proposed system increases the number of publishers, makes the publication process fully traceable, and makes scientific papers globally available to anyone with a small fee. In addition, the system provides journals with decentralized models and integrates scientific papers with related data or datasets. The editors, reviewers, and cited authors are also rewarded. The proposed system has been implemented using Ethereum Virtual Machine (EVM), which consists of a front-end, middleware, and back-end. When an author submits a manuscript for evaluation, the system automatically finds the most appropriate editors and reviewers for related fields. After the publication process finishes, editors, reviewers, cited authors, and other contributors are rewarded as a system token-based cryptocurrency.

Remote monitoring systems are vital for many systems. Especially in the broadcasting industry, it is critical to keep the broadcasts running 24/7 uninterrupted. It is another challenge to be aware of the interruptions in terrestrial broadcasts on the country's geography and to intervene as soon as possible. For this reason, it is aimed to monitor TRT (Turkish Radio Television Co.) FM and TV transmitters and to gather information about their malfunctions and following station security warning. With the developed system, the follow-up of those responsible has been facilitated, and the response times have been shortened and with the help of motion-sensitive cameras, the security level was increased by taking pictures in the OMC (Operation Monitoring Center). In addition, it is recommended to have appropriate spare materials by ensuring that the teams have information about the type of failure.