Computer Engineering / Bilgisayar Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/10
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Article Citation - WoS: 9Citation - Scopus: 13Microservice-Based Projects in Agile World: a Structured Interview(Elsevier, 2024) Unlu, Huseyin; Kennouche, Dhia Eddine; Soylu, Gorkem Kiling; Demirors, OnurContext: During the last decade, Microservice-based software architecture (MSSA) has been a preferred design paradigm for a growing number of companies. MSSA, specifically in the form of reactive systems, has substantial differences from the more conventional design paradigms, such as object-oriented analysis and design. Therefore, adaptation demands software organizations to transform their culture. However, there is a lack of research studies that explore common practices utilized by software companies that implement MSSAs.Objective: In this study, our goal is to get an insight into how practices such as an agile methodology, software analysis, design, test, size measurement, and effort estimation are performed in software projects which embrace the Microservice-based software architecture paradigm. Together with the identification of practices utilized for the MSSA paradigm, we aim to determine the challenges organizations face to adopt microservice-based software architectures.Method: We performed a structured interview with participants coming from 20 different organizations over different roles, domains, and countries to collect information on their views, experience, and the challenges faced.Results: Our results reveal that organizations find agile development compatible with microservices. In general, they continue to use traditional object-oriented modeling notations for analysis and design in an abstract way. They continue to use the same subjective size measurement and effort estimation approaches that they were using previously in traditional architectures. However, they face unique challenges in developing microservices.Conclusion: Although organizations face challenges, practitioners continue to use familiar techniques that they have been using for traditional architectures. The results provide a snapshot of the software industry that utilizes microservices.Article Citation - Scopus: 1An Interestingness Measure for Knowledge Bases(Elsevier, 2023) Oğuz, Damla; Soygazi, FatihAssociation rule mining and logical rule mining both aim to discover interesting relationships in data or knowledge. In association rule mining, relationships are identified based on the occurrence of items in a dataset, while in logical rule mining, relationships are determined based on logical relationships between atoms in a knowledge base. Association rule mining has been widely studied in transactional databases, mainly for market basket analysis. Confidence has become the most widely used interesting measure to assess the strength of a rule. Many other interestingness measures have been proposed since confidence can be insufficient to filter negatively associated relationships. Recently, logical rule mining has become an important area of research, as new facts can be inferred by applying discovered logical rules. They can be used for reasoning, identifying potential errors in knowledge bases, and to better understand data. However, there are currently only a few measures for logical rule mining. Furthermore, current measures do not consider relations that can have several objects, called quasi-functions, which can dramatically alter the interestingness of the rule. In this paper, we focus on effectively assessing the strength of logical rules. We propose a new interestingness measure that takes into account two categories of relations, functions and quasi-functions, to assess the degree of certainty of logical rules. We compare our proposed measure with a widely used measure on both synthetic test data and real knowledge bases. We show that it is more effective in indicating rule quality, making it an appropriate interestingness measure for logical rule evaluation. & COPY; 2023 Karabuk University. Publishing services by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Article Citation - WoS: 3Citation - Scopus: 4Scalable Rfid Authentication Protocol Based on Physically Unclonable Functions(Elsevier, 2023) Kurt, Işıl; Alagöz, Fatih; Akgün, MeteRadio Frequency Identification (RFID) technology is commonly used for tracking and identifying objects. However, this technology poses serious security and privacy concerns for individuals carrying the tags. To address these issues, various security protocols have been proposed. Unfortunately, many of these solutions suffer from scalability problems, requiring the back-end server to work linearly in the number of tags for a single tag identification. Some protocols offer O(1) or O(log n) identification complexity but are still susceptible to serious attacks. Few protocols consider attacks on the reader-side. Our proposed RFID authentication protocol eliminates the need for a search in the back-end and leverages Physically Unclonable Functions (PUFs) to securely store tag secrets, making it resistant to tag corruption attacks. It provides constant-time identification without sacrificing privacy and offers log2 n times better identification performance than the state-of-the-art protocol. It ensures destructive privacy for tag holders in the event of reader corruption without any conditions. Furthermore, it enables offline readers to maintain destructive privacy in case of corruption.Article Citation - WoS: 15Citation - Scopus: 18Achieving Query Performance in the Cloud Via a Cost-Effective Data Replication Strategy(Springer, 2021) Tos, Uras; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, TolgaMeeting performance expectations of tenants without sacrificing economic benefit is a tough challenge for cloud providers. We propose a data replication strategy to simultaneously satisfy both the performance and provider profit. Response time of database queries is estimated with the consideration of parallel execution. If the estimated response time is not acceptable, bottlenecks are identified in the query plan. Data replication is realized to resolve the bottlenecks. Data placement is heuristically performed in a way to satisfy query response times at a minimal cost for the provider. We demonstrate the validity of our strategy in a performance evaluation study.Article Citation - WoS: 1Citation - Scopus: 1Transcoding Web Pages Via Stylesheets and Scripts for Saving Energy on the Client(Wiley, 2022) Ünlü, Hüseyin; Yeşilada, YelizMobile devices and accessing the web have become essential in our daily lives. However, their limitations in terms of both hardware such as the battery, and software capabilities can affect the user experience such as battery drain. There are some best practices for the web page design that are shown to affect the downloading time of web pages. In this study, we report our experience in applying these practices to see their effect on energy saving. We propose two techniques: (1) concatenating external script and stylesheet files and (2) minifying external script and stylesheets that can be used to transcode web pages to improve energy consumption on the client-side and therefore improve the battery life. We present our experimental architecture, implementation, and a systematic evaluation of these two techniques. The evaluation results show that the proposed techniques can achieve approximately 12% processor energy-saving and 4% power saving in two different client types, 13% improvement in a typical laptop battery life, and 4% improvement in a typical mobile phone battery life.Article Citation - WoS: 55Citation - Scopus: 56Evaluation of an Artificial Intelligence System for Diagnosing Scaphoid Fracture on Direct Radiography(Springer Verlag, 2020) Özkaya, Emre; Topal, Fatih Esad; Bulut, Tuğrul; Gürsoy, Merve; Özuysal, Mustafa; Karakaya, ZeynepPurpose The aim of this study is to determine the diagnostic performance of artificial intelligence with the use of convolutional neural networks (CNN) for detecting scaphoid fractures on anteroposterior wrist radiographs. The performance of the deep learning algorithm was also compared with that of the emergency department (ED) physician and two orthopaedic specialists (less experienced and experienced in the hand surgery). Methods A total 390 patients with AP wrist radiographs were included in the study. The presence/absence of the fracture on radiographs was confirmed via CT. The diagnostic performance of the CNN, ED physician and two orthopaedic specialists (less experienced and experienced) as measured by AUC, sensitivity, specificity, F-Score and Youden index, to detect scaphoid fractures was evaluated and compared between the groups. Results The CNN had 76% sensitivity and 92% specificity, 0.840 AUC, 0.680 Youden index and 0.826Fscore values in identifying scaphoid fractures. The experienced orthopaedic specialist had the best diagnostic performance according to AUC. While CNN's performance was similar to a less experienced orthopaedic specialist, it was better than the ED physician. Conclusion The deep learning algorithm has the potential to be used for diagnosing scaphoid fractures on radiographs. Artificial intelligence can be useful for scaphoid fracture diagnosis particularly in the absence of an experienced orthopedist or hand surgeon.Article Citation - WoS: 58Citation - Scopus: 72A Reference Model for Bim Capability Assessments(Elsevier Ltd., 2019) Yılmaz, Gökçen; Akçamete, Aslı; Demirörs, OnurVarious BIM capability and maturity models have been developed to assist architecture, engineering, construction and facilities management (AEC/FM) organizations in measuring the performance of their BIM utilizations. Due to differences in applicability and focus of these models, they are able to meet the demands of different BIM users. In this study, eight BIM capability and maturity models identified in the literature are compared based on several different criteria. The results show that there is no holistic model that includes process definitions that cover the facility life-cycle and contains measures for assessing all of these AEC/FM processes. A reference model for assessing BIM capability of AEC/FM processes was developed. It was grounded on the meta-model of ISO/IEC 330xx family of standards and developed iteratively via expert reviews and an exploratory case study. It includes AEC/FM processes which were evaluated using the BIM capability levels, their associated BIM attributes, and a four-point rating scale. BIM-CAREM was evaluated by conducting four explanatory case studies. The results showed that BIM-CAREM was capable of identifying BIM capabilities of different AEC/FM processes.Article Citation - WoS: 23Citation - Scopus: 31A Survey on Multithreading Alternatives for Soft Error Fault Tolerance(Association for Computing Machinery (ACM), 2019) Öz, Işıl; Arslan, SanemSmaller transistor sizes and reduction in voltage levels in modern microprocessors induce higher soft error rates. This trend makes reliability a primary design constraint for computer systems. Redundant multithreading (RMT) makes use of parallelism in modern systems by employing thread-level time redundancy for fault detection and recovery. RMT can detect faults by running identical copies of the program as separate threads in parallel execution units with identical inputs and comparing their outputs. In this article, we present a survey of RMT implementations at different architectural levels with several design considerations. We explain the implementations in seminal papers and their extensions and discuss the design choices employed by the techniques. We review both hardware and software approaches by presenting the main characteristics and analyze the studies with different design choices regarding their strengths and weaknesses. We also present a classification to help potential users find a suitable method for their requirement and to guide researchers planning to work on this area by providing insights into the future trend.Article Citation - WoS: 9Citation - Scopus: 8Scalable Parallel Implementation of Migrating Birds Optimization for the Multi-Objective Task Allocation Problem(Springer Verlag, 2021) Öz, Dindar; Öz, IşılAs the distributed computing systems have been widely used in many research and industrial areas, the problem of allocating tasks to available processors in the system efficiently has been an important concern. Since the problem is proven to be NP-hard, heuristic-based optimization techniques have been proposed to solve the task allocation problem. Particularly, the current cloud-based systems have been grown massively requiring multiple features like lower cost, higher reliability, and higher throughput; therefore, the problem has become more challenging and approximate methods have gained more importance. Migrating birds optimization (MBO) algorithm offers successful solutions, especially for quadratic assignment problems. Inspired by the movement of the birds, it exhibits good results by its population-based approach . Since the algorithm needs to deal with many individuals in the population, and the neighbor solution generation phase takes substantial time for large problem instances, we need parallelism to have execution time improvements and make the algorithm practical for large-scale problems. In this work, we propose a scalable parallel implementation of the MBO algorithm, PMBO, for the multi-objective task allocation problem. We redesigned the implementation of the MBO algorithm so that its computationally heavy independent tasks are executed concurrently in separate threads. We compare our implementation with three parallel island-based approaches. The experimental results demonstrate that our implementation exhibits substantial solution quality improvements for difficult problem instances as the computing resources, namely parallelism, increase. Our scalability analysis also presents that higher parallelism levels offer larger solution improvement for the PMBO over the island-based parallel implementations on very hard problem instances.