Browsing by Subject "Blockchain"
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Item Open Access Applying Blockchain to Improve the Integrity of the Software Development Process(Springer, Cham, 2019) Yılmaz, M.; Taşel, S.; Güleç, Ulaş; Clarke; O’Connor, R. V.; Clarke, P. M.Software development is a complex endeavor that encompasses application and implementation layers with functional (refers to what is done) and non-functional (how is done) aspects. The efforts to scale agile software development practices are not wholly able to address issues such as integrity, which is a crucial non-functional aspect of the software development process. However, if we consider most software failures are Byzantine failures (i.e., where components may fail and there is imperfect information on which a component has failed.) that might impair the operation but do not completely disable the production line. In this paper, we assume software practitioners who cause defects as Byzantine participants and claim that most software failures can be mitigated by viewing software development as the Byzantine Generals Problem. Consequently, we propose a test-driven incentive mechanism based on a blockchain concept to orchestrate the software development process where production is controlled by a similar infrastructure based on the working principles of blockchain. We discuss the model that integrates blockchain with the software development process, and provide some recommendations for future work to address the issues while orchestrating software production.Item Open Access Blok zinciri teknolojisi ile veri korunumu sağlanmış oylama uygulaması(IEEE, 2019-09) Gani, Yağız; Aşkaroğlu, Mustafa MertThe main concerns which are coming to mind in the digital voting and election applications are data manipulation or deletion. When these concerns are considered, Blokchain is a foremost technology which proved itself on disposal of distrust and providing security of the data. Therefore, a voting or election system which is implemented with using Blockchain technology enable us to minimize the concerns which are stated above. In this study, a blockchain based voting application which aims to prohibit data manipulation is developed.Item Open Access A cryptocurrency incentivized voluntary grid computing platform for DNA read alignment(Bilkent University, 2019-09) Özercan, Halil İbrahimThe main computational bottleneck of High Throughput Sequencing (HTS) data analysis is to map the reads to a reference genome, for which clusters are typically used. However, building clusters large enough to handle hundreds of petabytes of data is infeasible. Additionally, the reference genome is also periodically updated to x errors and include newly sequenced insertions, therefore in many large scale genome projects the reads are realigned to the new reference. Therefore, we need to explore volunteer grid computing technologies to help ameliorate the need for large clusters. However, since the computational demands of HTS read mapping is substantial, and the turnaround of analysis should be fast, we also need a method to motivate volunteers to dedicate their computational resources. For this purpose, we propose to merge distributed read mapping techniques with the popular blockchain technology. Cryptocurrencies such as Bitcoin calculate a value (called nonce) to ensure new block (i.e., \money") creations are limited and di cult in the system, however, this calculation serves no other practical purpose. Our solution (Coinami) introduces a new cryptocurrency called Halocoin, which rewards scienti c work with alternative minting. In Coinami, read alignment problems are published and distributed in a decentralized manner while volunteers are rewarded for their work. Authorities have two main tasks in our system: 1) inject new problem sets (i.e., \alignment problems") into the system, and 2) check for the validity of the results to prevent counterfeit.Item Open Access The impact of blockchain related name changes on corporate performance(Elsevier, 2020) Akyıldırım, E.; Corbet, S.; Şensoy, Ahmet; Yarovaya, L.This paper examines the impact of blockchain and crypto-related name changes on corporate and financial performance of the corporations. We document several pieces of evidence suggesting that companies who partake in such “crypto-exuberant” naming practices become more volatile and offer substantial and persistent stock market premiums as a reward for their corporate identity change. However, the retroactive name changes harm firm's short-term profitability and have a dampening effect on financial leverage of the company. This paper advances the Dotcom effect literature by providing novel results on the changing traditional pathways of price discovery and information flows after the announcement of corporate name changes to blockchain-related names. The identified contagion channels display that crypto-exuberant companies become more susceptible to cryptocurrency markets, which should interest regulators and investors.Item Open Access Kripto varlıkların medeni hukuk bağlamında incelenmesi(Bilkent University, 2024-05) Saygıoğlu, SılaGünümüzde gelişen teknoloji hayatın her alanını etkilemektedir. Bu gelişen teknolojilerden biri de kripto varlıklardır. Kripto varlıklar merkeziyetsiz ve anonim yapılarıyla dikkat çekmekte ve yaygın bir şekilde kullanılmaktadır. Kripto varlıkların bu kadar yaygın kullanılması, hukuk dünyasını da etkilemektedir. Kripto varlıklar son yıllarda hem hukuk hem de ceza davalarına konu olmaya başlamıştır. Bu durum da kripto varlıkların hukuki durumunu belirlemeyi gerekli kılmıştır. Çalışmamızda öncelikle kripto varlıklar hakkında bilgi verilecek ve daha sonrasında dünyada ve ülkemizdeki düzenlemelere değinilecektir. Üçüncü bölümde kripto varlıkların hukuki niteliğinden bahsedilecektir. Dördüncü bölümde borçlar hukuku bağlamında bir inceleme yapılacaktır. Beşinci bölümde aile hukuku çerçevesinde kripto varlıklar incelendikten sonra son bölümde kripto varlıkların mirasçıya intikali konusundan bahsedilecektir. Önümüzdeki yıllardaki kripto varlıkların çok daha yaygın olarak kullanılacağı göz önünde tutulduğunda kripto varlıkların hukuk dünyasında da daha çok davaya konu olacağı açıktır. Bu yüzden de şimdiden ileride açılacak davalar için uygulamaya yol göstermek amacıyla kripto varlıkların medeni hukuk bağlamında hukuki niteliğinin aydınlatılması gerekmektedir.Item Open Access Towards modeling and mitigating misinformation propagation in online social networks(Bilkent University, 2023-01) Yılmaz, TolgaMisinformation on the internet and social media has become a pressing concern due to its potential impacts on society, undermining trust and impacting human decisions on global issues such as health, energy, politics, terrorism, and disasters. As a solution to the problem, computational methods have been employed to detect and mitigate the spread of false or misleading information. These efforts have included the development of algorithms to identify fake news and troll accounts, as well as research on the dissemination of misinformation on social media platforms. However, the problem of misinformation on the web and social networks remains a complex and ongoing challenge, requiring continued attention and research. We contribute to three different solution aspects of the problem. First, we design and implement an extensible social network simulation framework called Crowd that helps model, simulate, visualize and analyze social network scenarios. Second, we gamify misinformation propagation as a cooperative game between nodes and identify how misinformation spreads under various criteria. Then, we design a network-level game where the nodes are controlled from a higher perspective. In this game, we train and test a deep reinforcement learning method based on Multi-Agent Deep Deterministic Policy Gradients and show that our method outperforms well-known node-selection algorithms, such as page-rank, centrality, and CELF, over various social networks in defending against misinformation or participating in it. Finally, we promote and propose a blockchain and deep learning hybrid approach that utilizes crowdsourcing to target the misinformation problem while providing transparency, immutability, and validity of votes. We provide the results of extensive simulations under various combinations of well-known attacks on reputation systems and a case study that compares our results with a current study on Twitter.