Papers by Halit Oğuztüzün

One of the promises of High Level Architecture (HLA) is the reusability of simulation components.... more One of the promises of High Level Architecture (HLA) is the reusability of simulation components. Although HLA supports reusability to some extent with mechanisms provided by Object Model Template (OMT), when the developer wants to use an existing federate application within another federation with a different Federation Object Model (FOM) problem arises. She usually has to modify the federate code and rebuilt it. There have been some attempts to solve this problem and they, in fact, accomplish this to some extent but usually they fall short of providing flexible but also a complete mapping mechanism. In this work, a model based approach that mainly focuses on Declaration, Object and Federation Management services is explored. The proposed approach makes use of Model Integrated Computing (MIC) and .NET 2.0 technologies by grouping federate transitioning activities into three well-defined phases, namely, modeling, automatic code generation and component generation. As a side product, a .NET 2.0 wrapper to Runtime Infrastructure (RTI) has been developed to help developers create IEEE 1516 compatible .NET 2.0 federates in a programming language independent way.

Journal of Naval Sciences and Engineering, Jul 1, 2010
Training in a distributed simulation generally involves carefully designed and constructed simula... more Training in a distributed simulation generally involves carefully designed and constructed simulation scenarios to fulfill the training aims. The simulation scenarios (i.e. federation scenario) play an important role in the federation design and development as specified in Federation Development and Execution Process. The simulation scenarios are used in every step in distributed simulation arena from the beginning (analysis and design) of a distributed simulation development to the execution. Such an extensive use of scenarios in a distributed simulation dictates a scenario management. In a distributed simulation, the scenario management includes the activities of scenario development, scenario loading, scenario distribution, event injection, and scenario-related data collection in a distributed training. This article explains the major concepts of simulation scenarios, introduces a scenario object model, and discusses the main activities in scenario management in a distributed simulation with a practical view. This article also presents a running real-life example of a naval distributed interactive simulation to illustrate the scenario management activities. Özetçe Dağıtık simülasyonda eğitim, eğitim amaçlarını karşılamak maksadıyla genellikle dikkatlice oluşturulmuş ve tasarlanmış simülasyon senaryolarını içermektedir. Simülasyon senaryoları (diğer bir deyişle federasyon senaryoları), Federasyon Geliştirme ve Koşturma Prosesi'nde belirtilen federasyon tasarımı ve geliştirilmesi için önemli bir rol oynamakta ve aynı zamanda simülasyon senaryoları, dağıtık simülasyon alanında bir simülasyonun geliştirilmesinin başlangıcından (analiz ve tasarım) icrasına kadar tüm basamaklarında kullanılmaktadırlar. Dağıtık simülasyonda senaryoların böylesine yoğun kullanımı senaryo yönetimini zorunlu kılmaktadır. Dağıtık bir simülasyonda senaryo yönetimi; senaryonun geliştirilmesi, senaryonun yüklenmesi, senaryonun dağıtımı, olay enjektesi ve dağıtık eğitimde senaryoya bağımlı veri toplanması aktivitelerini içermektedir. Bu makale simülasyon senaryolarının temel kavramlarını açıklamakta, bir senaryo nesne modeli tanıtmakta ve pratik açıdan dağıtık bir simülasyonda ki temel senaryo yönetim aktivitelerini tartışmaktadır. Bu makale aynı zamanda senaryo yönetim aktivitelerini açıklamak için makale boyunca dağıtılmış bir şekilde gerçek bir deniz dağıtık etkileşimli simülasyon örneği sunmaktadır.

Sensors, Jan 16, 2020
Many industries, such as manufacturing, aviation, and power generation, employ sensitive measurem... more Many industries, such as manufacturing, aviation, and power generation, employ sensitive measurement devices to be calibrated by certified experts. The diversity and sophistication of measurement devices and their calibration needs require networked and automated solutions. Internet of Measurement Things (IoMT) is an architectural framework that is based on the Industrial Internet of Things for the calibration industry. This architecture involves a layered model with a cloud-centric middle layer. In this article, the realization of this conceptual architecture is described. The applicability of the IoMT architecture in the calibration industry is shown through an editor application for Scope of Accreditation. The cloud side of the implementation is deployed to Microsoft Azure. The editor itself is created as a cloud service, and IoT Hub is used to collect data from calibration laboratories. By adapting the IoMT architecture to a commonly used cloud platform, considerable progress is achieved to encompass Metrology data and serve the majority of the stakeholders.

Scenario development starts with capturing scenarios from the users and leads to the design and t... more Scenario development starts with capturing scenarios from the users and leads to the design and the development of the simulation environment to execute these scenarios. This paper proposes a scenario development process adopting a Model-Driven Engineering (MDE) perspective. It takes scenario development and the use of scenarios in simulation environment development put forth in IEEE Recommended Practice for Distributed Simulation Engineering and Execution Process (DSEEP) as a starting point. It then constructs a basic vocabulary including the definitions of operational, conceptual, and executable scenarios. Following MDE principles, scenario development is viewed as a series of model transformations. Operational scenarios, mostly defined in a natural language, are first transformed into conceptual scenarios, which conform to a formal metamodel. Then conceptual scenarios can be transformed into executable scenarios specified using a specific scenario definition language. Furthermore, it is also possible to generate the constructs of simulation environment design and development using model transformations. In this regard, a conceptual scenario metamodel is proposed adopting the Base Object Model metamodel as an example. Then this metamodel is used to present the proposed process with a sample operational scenario and conceptual scenario excerpts. Samples are shown how model transformation can be employed for developing a Federation Object Model and an executable scenario file.
Querying Fuzzy Spatiotemporal Databases: Implementation Issues
Studies in computational intelligence, 2010
Modeling and querying spatiotemporal data, in particular fuzzy and complex spatial objects repres... more Modeling and querying spatiotemporal data, in particular fuzzy and complex spatial objects representing geographic entities and relations are challenging topics that have many applications in geographic information systems. In a recent article the authors have presented an approach to these problems. The present chapter focuses on the issues that arise from implementing this approach. As a case study the implementation

IEEE Transactions on Fuzzy Systems, Oct 1, 2015
Spatiotemporal data, in particular fuzzy and complex spatial objects representing geographic enti... more Spatiotemporal data, in particular fuzzy and complex spatial objects representing geographic entities and relations, is a topic of great importance in geographic information systems and environmental data management systems. For database researchers, modeling and designing a database of fuzzy spatiotemporal data and querying such a database efficiently have been challeging issues due to complex spatial features and uncertainty involved. This article presents an integrated approach to modeling, indexing and efficiently querying spatiotemporal data related to fuzzy spatial and complex objects and spatial relations. As our case study, we design and implement a meteorological database application that involves fuzzy spatial and complex objects, and a spatiotemporal index structure, and supports various types of spatial queries including fuzzy spatiotemporal queries. Our implementation is based on an intelligent database system architecture that combines a fuzzy object-oriented database with a fuzzy knowledge base.

Turkish Journal of Electrical Engineering and Computer Sciences, Sep 18, 2019
For real-time simulations, the fidelity of simulation depends not only on the functional accuracy... more For real-time simulations, the fidelity of simulation depends not only on the functional accuracy of simulation but also on its timeliness. It is helpful for simulation designers if they can analyze and verify that a simulation will always meet its timing requirements without unnecessarily sacrificing functional accuracy. Abstracting the simulated processes simply as software tasks allows us to transform the problem of verifying timeliness into a schedulability analysis problem where tasks are checked as to whether they are schedulable under the timing constraints or not. In this paper we extend a timed automaton-based framework due to Fersman and Yi for schedulability analysis of real-time systems, for the special case of real-time multiframe cosimulations. To the best of our knowledge, this work is the first to analyze the schedulability of single-or multiframe real-time simulations. We found that there are some special requirements posed by multiframe simulations, which necessitate changes and improvements in the existing framework designed for actual real-time systems. We made the required theoretical extensions to the framework and implemented our extended framework in UPPAAL, a tool for modeling, simulation, and verification of real-time systems modeled as timed automata. The functional correctness and resource requirements of the implemented framework are then demonstrated using simple examples.
UYMS, 2013
Yazılım mimarisinin taşıdığı riskleri yazılım geliştirme yaşam döngüsünün erken evrelerinde tespi... more Yazılım mimarisinin taşıdığı riskleri yazılım geliştirme yaşam döngüsünün erken evrelerinde tespit edebilmek için yazılım mimarisinin sistematik değerlendirilmesi büyük önem taşımaktadır. Bu bildiride bir araştırma platformu olarak geliştirilen çoklu ortam veri yönetim sistemi mimarisinin, SEI (Software Engineering Institute) tarafından önerilen ATAM (Mimari Ödünleşim Analiz Metodu) kullanılarak değerlendirildiği vaka çalışması hakkında bilgi verilmektedir.
Software architecture of a Multimedia Data Management System
Multimedia Data Management Systems (MMDMS) enable accessing, storing, organizing and retrieving m... more Multimedia Data Management Systems (MMDMS) enable accessing, storing, organizing and retrieving multimedia content effectively and efficiently. The primary objective of the paper is to describe the software architecture of Middle East Technical University Multimedia Data Management System (METU-MMDMS) to facilitate future research on MMDMSs. There is a lack of published descriptive architectures for similar systems. Therefore, describing a particular MMDMS architecture, investigating the design decisions, rationale and the variability points that are parts of the MMDMS architectural design, showing that the prepared MMDMS architecture documentation has enough substance to account for the required scenarios are discussed in this paper.

In this work, we present an event detection method in Twitter based on clustering of hashtags and... more In this work, we present an event detection method in Twitter based on clustering of hashtags and introduce an enhancement technique by using the semantic similarities between the hashtags. To this aim, we devised two methods for tweet vector generation and evaluated their effect on clustering and event detection performance in comparison to word-based vector generation methods. By analyzing the contexts of hashtags and their co-occurrence statistics with other words, we identify their paradigmatic relationships and similarities. We make use of this information while applying a lexico-semantic expansion on tweet contents before clustering the tweets based on their similarities. Our aim is to tolerate spelling errors and capture statements which actually refer to the same concepts. We evaluate our enhancement solution on a three-day dataset of tweets with Turkish content. In our evaluations, we observe clearer clusters, improvements in accuracy, and earlier event detection times.

Springer eBooks, 2011
Multidimensional datasets are getting more extensively used in Geographic Information Systems (GI... more Multidimensional datasets are getting more extensively used in Geographic Information Systems (GIS) applications in recent years. Due to large volume of these datasets efficient querying becomes a significant problem. For this purpose, before creating index structure with these enormous datasets, choosing an efficient index structure is an urgent necessity. The aim of this thesis is to develop an efficient, flexible and extendible index structure which comprises 3D spatial data in primary index and fuzzy attributes in secondary index. These primary and secondary indexes are handled in a coupled structure. Firstly, a 3D spatial primary index is built by using X-tree structure, and then a fuzzy secondary index is overlaid over the X-tree structure. The coupled structure is shown more efficient on a certain class of queries than uncoupled index structures comprising 3D spatial data in primary index and fuzzy attributes in secondary index separately. In uncoupled index structure, we provided 3D spatial primary index by using X-tree index structure and fuzzy secondary index by using BPlusTree index structure.

Proceedings of the First International IMEKO TC6 Conference on Metrology and Digital Transformation - M4Dconf2022, 2022
Providing automated and networked solutions on the cloud will remarkably facilitate ongoing digit... more Providing automated and networked solutions on the cloud will remarkably facilitate ongoing digitalization efforts in Metrology and the calibration industry. The AutoRFPower application was developed to automate the RF power measurement process and uncertainty calculations. This study presents our ongoing research on moving this application to a cloud environment and adapting it to perform power sensor calibrations. The cloud-based application initiates communication with calibration equipment, transfers test points to the client computer to perform measurement activities locally, and finally transfers the measurement data back to the cloud. Uncertainty calculations are performed on the cloud by a service. The calibration process produces a digital calibration certificate again on the server-side. The structure of the cloud-based application conforms to our previously proposed Internet of Measurement Things architecture, paving the way for digitalization and standardization in Metrology and the calibration industry.

International Journal of Simulation Modelling, 2022
Most of the frameworks or assistance systems for experiment specification do not provide a proces... more Most of the frameworks or assistance systems for experiment specification do not provide a process explicitly based on formally specified hypotheses. This deficiency leads to inaccurate or insufficient record of an experiment, decreasing the trustworthiness and reproducibility of the experiment. Moreover, the wide variety of models, metamodels, tools, and data for experimentation requires Global Model Management (GMM) that is utilizing Model-Driven Engineering techniques, facilitates documentation, sharing, reusability, and replicability of simulation experiments. In this study, we strive to illustrate how to support simulation experimentation with hypotheses as a scientific workflow through GMM with an extension to the Simulation Experiment Description Mark-up Language (SED-ML). In particular, we present a megamodel built to serve as a repository to manage the artefacts employed in a simulation experiment. Based on the SED-ML, and enriched with hypothesis handling, our megamodel attempts to address all the phases of a simulation experiment, including specification, input data generation, execution, and output data analysis.

The Internet of Things in the Industrial Sector, 2019
Many improvements have been realized in various domains, whether commercial or societal, through ... more Many improvements have been realized in various domains, whether commercial or societal, through the use of the Internet of Things (IoT) vision, since the introduction of the IoT concept some two decades ago. Nowadays, the benefits that IoT technologies promise are becoming highly attractive for the industrial domain, in particular. There is no doubt that manufacturing of products, processing of big data produced in the production phases and gathering of customer behavior profiles, increases the efficiency of production, reduces the time to market and decreases the operational costs. This new approach that uses IoT based smart devices and intelligent sensors is called the Industrial Internet of Things (IIoT). Major global companies from various sectors such as manufacturing, automotive, mining and aviation are all taking advantage of the IIoT paradigm. The related technologies also provide limitless opportunities for the calibration industry. In turn, the world of IIoT needs to be provided with accurate and timely calibration information to increase the efficiency of processes. Having many sensitive measurement devices from customers to be calibrated by certified experts calls for networked and automated solutions. This chapter proposes an IIoT-based solution that could evolve into an architectural framework for the calibration industry.
Özet. Yazılım mimarisinin taşıdığı riskleri yazılım geliştirme yaşam döngüsünün erken evrelerinde... more Özet. Yazılım mimarisinin taşıdığı riskleri yazılım geliştirme yaşam döngüsünün erken evrelerinde tespit edebilmek için yazılım mimarisinin sistematik değerlendirilmesi büyük önem taşımaktadır. Bu bildiride bir araştırma platformu olarak geliştirilen çoklu ortam veri yönetim sistemi mimarisinin, SEI (Software Engineering Institute) tarafından önerilen ATAM (Mimari Ödünleşim Analiz Metodu) kullanılarak değerlendirildiği vaka çalışması hakkında bilgi verilmektedir.
Özetçe Günümüzdeki büyük ölçekli kurumsal yaplarda, ³ Süreçleri Yönetimi kritik bir önem ta³makta... more Özetçe Günümüzdeki büyük ölçekli kurumsal yaplarda, ³ Süreçleri Yönetimi kritik bir önem ta³maktadr. Süreçlerin modellenmesi; i³lerin tanmlanmas, analiz edilmesi, yönetilmesi ve kontrol edilmesi açsndan kritiktir. ³ süreçleri modelleme ayn zamanda, süreçlerin ve kritik seviyelerdeki hedeerin arasndaki ili³kileri kurmak açsndan da önemlidir. Bu çal³mada, i³ süreçleri modellemenin i³levsel olan ve olmayan açlarna getirilen yeni yakla³mlar için üretilen görsel ve i³levsel bir araç anlatlmaktadr. Süreçlerin hedeerle ili³kilendirilmesini sa §layan bir yöntem için yeni bir araç geli³tirilmi³ ve bu aracn ayn zamanda hedeer arasndaki saysal ili³kileri de kurmas sa §lanm³tr.

Data and behavior decomposition for the model-driven development of an executable simulation model
In a previous work, we have presented a two step automatic transformation of Field Artillery Conc... more In a previous work, we have presented a two step automatic transformation of Field Artillery Conceptual Model (ACM) into High Level Architecture (HLA) Federation Architecture Model (FAM) into executable distributed simulation code. The approach followed adheres to the Model-Driven Engineering (MDE) philosophy. ACM is comprised of a data component, based on UML class diagrams, and a behavioral component, based on Live Sequence Chart (LSC). The ACM modeling and its transformation to FAM for the common Adjustment Followed by Fire For Effect (AdjFFE) mission has been presented as the case study. BatteryFDC, which is an abstraction of a battery's fire direction center, is the central LSC instance in ACM. In this paper we focus inside the BatteryFDC, develop its lower level decomposed conceptual model, called Fire Direction Center Conceptual Model (FDCCM). Then FDCCM modeling for the AdjFFE mission pertaining to FDC scope and its transformation to FAM is demonstrated. Finally, simulat...
Interoperability is a challenge for constructing Live-Virtual-Constructive (LVC) systems. This st... more Interoperability is a challenge for constructing Live-Virtual-Constructive (LVC) systems. This study is a step toward LVC interoperability adhering to a gateway-based approach with a particular focus on two standard middleware, namely, Data Distribution Service for Real-Time Systems (DDS) and High-Level Architecture (HLA) for distributed simulation. A gateway is designed and implemented to achieve DDS-HLA interoperability. This gateway has the ability to realize two-way data transfer between DDS and HLA systems. The gateway design is based on the idea of a configurable connector that is equipped with variability capabilities. It can perform data-type conversions between these two systems according to the mappings specified by the user. In a case study, the gateway is integrated into a distributed tactical environment simulation system.

Proceedings of the 5th International Conference on Simulation and Modeling Methodologies, Technologies and Applications, 2015
Distributed Discrete Event System Specification (DEVS) environments are developed with various co... more Distributed Discrete Event System Specification (DEVS) environments are developed with various computing, networking and implementation language options. We propose a distributed approach to the Simulation Modeling Architecture (SiMA), a DEVS-based modeling and simulation framework, with software connectors. We employ Windows Communication Foundation (WCF) as the middleware technology. A connector is a first class entity which performs interaction among components, thus, plays an important role in a component-based architecture. We claim that using a connector instead of modifying an already developed model increases the model reusability. We also compare this approach with the existing distributed DEVS approaches in terms of base formalism, network layer technology, model partitioning, remote node synchronization scheme and message exchange pattern.

Using context information for staged configuration of feature models
Journal of Integrated Design and Process Science
Since their introduction feature models have been widely accepted and used in Software Product Li... more Since their introduction feature models have been widely accepted and used in Software Product Lines. However, feature models may become too large easily, which complicates the management of the model. One of the reasons of complexity arises from the constraints imposed by the context on the product family. In this article we propose a strategy that uses context information for performing staged configurations on feature models. We introduce an organization structure for the context variability model and use this organization to determine the configurations for specification stages. This approach enables the elimination of context-related variability from the feature model, thus results in a reduction in the complexity of the model and enables to focus on the functional features of the product family.
Uploads
Papers by Halit Oğuztüzün