Computer Engineering / Bilgisayar Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/10

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Now showing 1 - 20 of 342

Citation - WoS: 5
Citation - Scopus: 6
The 1st Workshop on Model-Based Verification & Validation: Directed Acyclic Graph Modeling of Security Policies for Firewall Testing
(Institute of Electrical and Electronics Engineers Inc., 2009) Tuğlular, Tuğkan; Kaya, Özgür; Müftüoğlu, Can Arda; Belli, Fevzi
Currently network security of institutions highly depend on firewalls, which are used to separate untrusted network from trusted one by enforcing security policies. Security policies used in firewalls are ordered set of rules where each rule is represented as a predicate and an action. This paper proposes modeling of firewall rules via directed acyclic graphs (DAG), from which test cases can be automatically generated for firewall testing. The approach proposed follows test case generation algorithm developed for event sequence graphs. Under a local area network setup with the aid of a specifically developed software for this purpose, generated test cases are converted to network test packets, test packets are sent to the firewall under test (FUT), and sent packets are compared with passed packets to determine test result.
Citation - WoS: 1
Citation - Scopus: 1
Accounting for Product Similarity in Software Project Duration Estimation
(World Scientific Publishing Co. Pte Ltd, 2016-02-01) Taştekin, Semra Yılmaz; Erten, Yusuf Murat; Bilgen, Semih
We extend an existing model proposed for estimating project duration for industrial projects in general, to software intensive systems projects. We show, through nine different cases studies from different sectors, that product similarity, measured in terms of requirements reuse, can be incorporated into that model to improve its applicability in software intensive systems projects.
Citation - WoS: 15
Citation - Scopus: 18
Achieving Query Performance in the Cloud Via a Cost-Effective Data Replication Strategy
(Springer, 2021) Tos, Uras; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, Tolga
Meeting 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.
Citation - WoS: 18
Citation - Scopus: 25
Adaptation and Use of Subjectivity Lexicons for Domain Dependent Sentiment Classification
(Institute of Electrical and Electronics Engineers Inc., 2012) Dehkharghani, Rahim; Yanıkoğlu, Berrin; Tapucu, Dilek; Saygın, Yücel
Sentiment analysis refers to the automatic extraction of sentiments from a natural language text. We study the effect of subjectivity-based features on sentiment classification on two lexicons and also propose new subjectivity-based features for sentiment classification. The subjectivity-based features we experiment with are based on the average word polarity and the new features that we propose are based on the occurrence of subjective words in review texts. Experimental results on hotel and movie reviews show an overall accuracy of about 84% and 71% in hotel and movie review domains respectively; improving the baseline using just the average word polarities by about 2% points. © 2012 IEEE.
Citation - Scopus: 2
Adapting Spice for Development of a Reference Model for Building Information Modeling - Bim-Carem
(Springer Verlag, 2018) Yılmaz, Gökçen; Akçamete, Aslı; Demirörs, Onur
Building Information Modelling (BIM) is highly adopted by Architecture, Engineering, Construction and Facilities Management (AEC/FM) companies around the world due to its benefits such as improving collaboration of stakeholders in projects. Effective implementation of BIM in organizations requires assessment of existing BIM performances of AEC/FM processes. We developed a reference model for BIM capability assessments based on the meta-model of the ISO/IEC 330xx (the most recent version of SPICE) family of standards. BIM-CAREM can be used for identifying the BIM capabilities of the AEC/FM processes. The model was updated iteratively based on the expert reviews and an exploratory case study, and was evaluated via four explanatory case studies. The assessment results showed that the BIM-CAREM is capable of identifying BIM capabilities of specific processes. In this paper, we present how we utilized ISO/IEC 330xx for developing BIM-CAREM as well as the iterations of the model and one of the explanatory case studies as an example.
Citation - Scopus: 2
Adaptive Join Operator for Federated Queries Over Linked Data Endpoints
(Springer Verlag, 2016) Oğuz, Damla; Yin, Shaoyi; Hameurlain, Abdelkader; Ergenç, Belgin; Dikenelli, Oğuz
Traditional static query optimization is not adequate for query federation over linked data endpoints due to unpredictable data arrival rates and missing statistics. In this paper, we propose an adaptive join operator for federated query processing which can change the join method during the execution. Our approach always begins with symmetric hash join in order to produce the first result tuple as soon as possible and changes the join method as bind join when it estimates that bind join is more efficient than symmetric hash join for the rest of the process. We compare our approach with symmetric hash join and bind join. Performance evaluation shows that our approach provides optimal response time and has the adaptation ability to the different data arrival rates.
Citation - Scopus: 9
Adaptive Rtp Rate Control Method
(Institute of Electrical and Electronics Engineers Inc., 2011-10) Tos, Uras; Ayav, Tolga
In this paper, we present an adaptive method for maximizing network bandwidth utilization for the real-time applications. RTP protocol is chosen as the transport protocol and the network utilization is provided by increasing and decreasing the transmission rate of the RTP traffic. Our method employs a PID controller that keeps the RTP packet loss fraction at a predefined reference point. Packet loss fraction parameter is gathered from the RTCP receiver reports and fed into the PID controller that controls the transmission rate of the RTP traffic. Simulations are performed to demonstrate the effectiveness of the method under a bottleneck network configuration with background UDP traffic competing against the RTP traffic for the available bandwidth.
Citation - WoS: 1
Citation - Scopus: 3
Adopting Heterogeneous Computing Modules: Experiences From a Touch Summer Workshop
(Institute of Electrical and Electronics Engineers Inc., 2022) Bunde, D.P.; Ahmed, K.; Ayloo, S.; Brown-Gaines, T.; Fuentes, J.; Jatala, V.; Yeh, T.Y.
We present efforts to encourage the adoption of modules for teaching heterogeneous parallel computing through a faculty development workshop. The workshop was held remotely using a novel format to exploit the advantages of a virtual format and mitigate its disadvantages. Adoption at a wide variety of institutions showed module effectiveness and also gathered feedback leading to several module improvements. We also report on the adoptions themselves, which show the importance of supporting adaptation of the modules for diverse settings. © 2022 IEEE.
Citation - WoS: 4
Citation - Scopus: 8
Advances in Model-Based Testing of Graphical User Interfaces
(Academic Press Inc., 2017) Belli, Fevzi; Beyazıt, Mutlu; Budnik, Christof J.; Tuğlular, Tuğkan
Graphical user interfaces (GUIs) enable comfortable interactions of the computer-based systems with their environment. Large systems usually require complex GUIs, which are commonly fault prone and thus are to be carefully designed, implemented, and tested. As a thorough testing is not feasible, techniques are favored to test relevant features of the system under test that will be specifically modeled. This chapter summarizes, reviews, and exemplifies conventional and novel techniques for model-based GUI testing.
Citation - WoS: 3
Citation - Scopus: 4
Affordable person detection in omnidirectional cameras using radial integral channel features
(Springer Verlag, 2019) Demiröz, Barış Evrim; Salah, Albert Ali; Baştanlar, Yalın; Akarun, Lale
Omnidirectional cameras cover more ground than perspective cameras, at the expense of resolution. Their comprehensive field of view makes omnidirectional cameras appealing for security and ambient intelligence applications. Person detection is usually a core part of such applications. Conventional methods fail for omnidirectional images due to different image geometry and formation. In this study, we propose a method for person detection in omnidirectional images, which is based on the integral channel features approach. Features are extracted from various channels, such as LUV and gradient magnitude, and classified using boosted decision trees. Features are pixel sums inside annular sectors (doughnut slice shapes) contained by the detection window. We also propose a novel data structure called radial integral image that allows to calculate sums inside annular sectors efficiently. We have shown with experiments that our method outperforms the previous state of the art and uses significantly less computational resources.
Citation - WoS: 5
Citation - Scopus: 10
Algorithmic Decision of Syllogisms
(Springer Verlag, 2010) Kumova, Bora İsmail; Çakır, Hüseyin
A syllogism, also known as a rule of inference, is a formal logical scheme used to draw a conclusion from a set of premises. In a categorical syllogisms, every premise and conclusion is given in form a of quantified relationship between two objects. The syllogistic system consists of systematically combined premises and conclusions to so called figures and moods. The syllogistic system is a theory for reasoning, developed by Aristotle, who is known as one of the most important contributors of the western thought and logic. Since Aristotle, philosophers and sociologists have successfully modelled human thought and reasoning with syllogistic structures. However, a major lack was that the mathematical properties of the whole syllogistic system could not be fully revealed by now. To be able to calculate any syllogistic property exactly, by using a single algorithm, could indeed facilitate modelling possibly any sort of consistent, inconsistent or approximate human reasoning. In this paper we present such an algorithm.
Citation - Scopus: 9
An Analysis of Large Language Models and Langchain in Mathematics Education
(Association for Computing Machinery, 2023) Soygazi,F.; Oğuz, Damla
The development of large language models (LLMs) has led to the consideration of new approaches, particularly in education. Word problems, especially in subjects like mathematics, and the need to solve these problems by collectively addressing specific stages of reasoning, have raised the question of whether LLMs can be successful in this area as well. In our study, we conducted analyses by asking mathematics questions especially related to word problems using ChatGPT, which is based on the latest language models like Generative Pretrained Transformer (GPT). Additionally, we compared the correct and incorrect answers by posing the same questions to LLMMathChain, a mathematics-specific LLM based on the latest language models like LangChain. It was observed that the answers obtained were more successful with ChatGPT (GPT 3.5), particularly in the field of mathematics. However, both language models were found to be below expectations, particularly in word problems, and suggestions for improvement were provided. © 2023 ACM.
An Analysis of Rumor Spreading Fundamentals With a Case Study on Facebook
(Karabük Üniversitesi, 2018) Sayin, Burcu; Şahin, Serap
Nowadays, the effect of social networks on people's lives is quite high. This situation gives rise to the density of information exist over social networks. That is why, analyzing the spreading pattern of information on social networks is an important issue today. The aim of this study is to technically review the background of information spreading, especially the fundamentals of rumor spreading and analyze the well-known methods on SNs. As a result, this article provides an important background for those, who works on the information spreading over SNs.
Citation - WoS: 34
Citation - Scopus: 53
Application Areas of Community Detection: a Review
(Institute of Electrical and Electronics Engineers Inc., 2019) Karatas, A.; Sahin, S.
In the realm of today's real world, information systems are represented by complex networks. Complex networks contain a community structure inherently. Community is a set of members strongly connected within members and loosely connected with the rest of the network. Community detection is the task of revealing inherent community structure. Since the networks can be either static or dynamic, community detection can be done on both static and dynamic networks as well. In this study, we have talked about taxonomy of community detection methods with their shortages. Then we examine and categorize application areas of community detection in the realm of nature of complex networks (i.e., static or dynamic) by including sub areas of criminology such as fraud detection, criminal identification, criminal activity detection and bot detection. This paper provides a hot review and quick start for researchers and developers in community detection area. © 2018 IEEE.
Citation - WoS: 15
Citation - Scopus: 25
Application of a Software Agility Assessment Model – Agilitymod in the Field
(Elsevier Ltd., 2019) Özcan Top, Özden; Demirörs, Onur
Adoption of agile values and principles and transformation of organizations towards agility are not easy and straightforward. Misinterpretation of agile principles and values, and adoption of partial solutions with few agile practices instead of holistic approaches prevent organizations to obtain full benefits of agile methods. We developed the Software Agility Assessment Reference Model (AgilityMod) for the appraisal of software projects from agility perspective and to provide guidance on specifying gaps on the road towards agility (agile maturity). The meta-model of AgilityMod was defined in relation with the ISO/IEC 15504-Process Assessment Model. AgilityMod was developed in an iterative and incremental manner by running successive case studies and getting opinions of experts for the evaluation and improvement of the Model. The multiple case study that we present here in detail included the implementation of the Model in eight software development companies. The results of this case study were evaluated by the case study participants. According to the significant majority of the case study participants, AgilityMod achieves its purpose.
Citation - WoS: 1
Citation - Scopus: 1
Application of Human-Robot Interaction Features To Design and Purchase Processes of Home Robots
(Springer, 2021) Yapıcı, Nur Beril; Tuğlular, Tuğkan; Başoğlu, Ahmet Nuri
Production of home robots, such as robotic vacuum cleaners, currently focuses more on the technology and its engineering than the needs of people and their interaction with robots. An observation supporting this view is that the home robots are not customizable. In other words, buyers cannot select the features and built their home robots to order. Stemmed from this observation, the paper proposes an approach that starts with a classification of features of home robots. This classification concerns robot interaction with humans and the environment, a home in our case. Following the classification, the proposed approach utilizes a new hybrid model based on a built-to-order model and dynamic eco-strategy explorer model, enabling designers to develop a production line and buyers to customize their home robots with the classified features. Finally, we applied the proposed approach to robotic vacuum cleaners. We developed a feature model for robotic vacuum cleaners, from which we formed a common uses scenario model.
Citation - WoS: 2
Citation - Scopus: 3
Application of the Law of Minimum and Dissimilarity Analysis To Regression Test Case Prioritization
(IEEE, 2023) Ufuktepe, Ekincan; Tuğlular, Tuğkan
Regression testing is one of the most expensive processes in testing. Prioritizing test cases in regression testing is critical for the goal of detecting the faults sooner within a large set of test cases. We propose a test case prioritization (TCP) technique for regression testing called LoM-Score inspired by the Law of Minimum (LoM) from biology. This technique calculates the impact probabilities of methods calculated by change impact analysis with forward slicing and orders test cases according to LoM. However, this ordering doesn't consider the possibility that consecutive test cases may be covering the same methods repeatedly. Thereby, such ordering can delay the time of revealing faults that exist in other methods. To solve this problem, we enhance the LoM-Score TCP technique with an adaptive approach, namely with a dissimilarity-based coordinate analysis approach. The dissimilarity-based coordinate analysis uses Jaccard Similarity for calculating the similarity coefficients between test cases in terms of covered methods and the enhanced technique called Dissimilarity-LoM-Score (Dis-LoM-Score) applies a penalty with respective on the ordered test cases. We performed our case study on 10 open-source Java projects from Defects4J, which is a dataset of real bugs and an infrastructure for controlled experiments provided for software engineering researchers. Then, we hand-seeded multiple mutants generated by Major, which is a mutation testing tool. Then we compared our TCP techniques LoM-Score and Dis-LoM-Score with the four traditional TCP techniques based on their Average Percentage of Faults Detected (APFD) results.
Applying Weighted Graph Embeddings To Turkish Metaphor Detection
(Institute of Electrical and Electronics Engineers Inc., 2024) İnan, Emrah
Metaphor is a common literary mechanism that allows abstract concepts to be conceptualised using more concrete terminology. Existing methods rely on either end-to-end models or hand-crafted pre-processing steps. Generating well-defined training datasets for supervised models is a time-consuming operation for this type of problem. There is also a lack of pre-processing steps for resource-poor natural languages. In this study, we propose an approach for detecting Turkish metaphorical concepts. Initially, we collect non-literal concepts including their meaning and reference sentences by employing a Turkish dictionary. Secondly, we generate a graph by discovering super-sense relations between sample texts including target metaphorical expressions in Turkish WordNet. We also compute weights for relations based on the path closeness and word occurrences. Finally, we classify the texts by leveraging a weighted graph embedding model. The evaluation setup indicates that the proposed approach reaches the best F1 and Gmean scores of 0.83 and 0.68 for the generated test sets when we use feature vector representations of the Node2Vec model as the input of the logistic regression for detecting metaphors in Turkish texts. © 2024 IEEE.
Citation - Scopus: 1
Approximate Reasoning With Fuzzy-Syllogistic Systems
(CEUR Workshop Proceedings, 2015) Kumova, Bora İsmail
The well known Aristotelian syllogistic system consists of 256 moods. We have found earlier that 136 moods are distinct in terms of equal truth ratios that range in τ=[0,1]. The truth ratio of a particular mood is calculated by relating the number of true and false syllogistic cases the mood matches. A mood with truth ratio is a fuzzy-syllogistic mood. The introduction of (n-1) fuzzy existential quantifiers extends the system to fuzzy-syllogistic systems nS, 1
Citation - Scopus: 4
An Architecture for Verification of Access Control Policies With Multi Agent System Ontologies
(Institute of Electrical and Electronics Engineers Inc., 2009) Tekbacak, Fatih; Tuğlular, Tuğkan; Dikenelli, Oğuz
Multi-agent systems (MAS) which communicate with intra-domain and inter-domain agent platforms have access control requirements. Instead of a central mechanism, a fine-graned access control mechanism could have been applied to MAS platforms. This paper emphasizes MAS-based domain and security ontologies with XACML-based access control approach for MAS platforms. The domain dependent behaviour and access control parameters in agent ontologies could be combined within a common XACML policy document that is used through different MAS applications. Agent-based access control requirements and common XACML policy documents should be consistent to enforce policies for MAS. To obtain this condition, the translation of organizational policies and platform based policies have to be considered in detail and the verified policy features have to be enforced in MAS to provide access for resources.

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