Yaşar University

About: Yaşar University is a education organization based out in Izmir, Turkey. It is known for research contribution in the topics: Exergy & Job shop scheduling. The organization has 760 authors who have published 1436 publications receiving 20813 citations. The organization is also known as: Yaşar Üniversitesi.

Utilization of Timed Automata as a Verification Tool for Security Protocols

Abstract: Timed Automata is an extension to the automata-theoretic approach for the modeling of real time systems that introduces time into the classical automata. It has become an important research area in both the context of formal languages and modeling and verification of real time systems since it was proposed by Alur and Dill in the early nineties. Timed automata proposes an efficient model checking method for verification real time systems having mature and efficient automatic verification tools. One of the application areas of timed automata is the verification of security protocols which are known to be time sensitive. This study aims to make use of timed automata as a verification tool for security protocols and gives a case study on the initial part of the Neuman-Stubblebine Repeated Authentication Protocol.

Hybrid models for suspended sediment prediction: optimized random forest and multi-layer perceptron through genetic algorithm and stochastic gradient descent methods

Abstract: Owing to the nonlinear and non-stationary nature of the suspended sediment transport in rivers, suspended sediment concentration (SSC) modeling is a challenging task in environmental engineering. Investigation of SSC is of paramount importance in river morphology and hydraulic structures operation. To this end, for SSC modeling, first random forest (RF) and multi-layer perceptron (MLP) standalone models were developed, and then, they were optimized with genetic algorithm (GA) and stochastic gradient descent (SGD) to develop GA-MLP, GA-RF, SGD-MLP, and SGD-RF hybrid models. Variety of input scenarios are implemented for SSC prediction to find the best input combination. The streamflow and SSC data collected from two stations of Minnesota and San Joaquin rivers, respectively, located at South Dakota and California are utilized in the current study. Accuracies of the developed models are examined by means of three performance criteria of correlation coefficient (CC), scattered index (SI), and Willmott’s index of agreement (WI). A significant promotion in accuracy of hybrid models has been seen in contrast to their standalone counterparts. As can be deduced from the results, GA-MLP-5 and GA-RF-5 models with CC of 0.950 and 0.944, SI of 0.290 and 0.308, and WI of 0.974 and 0.971, respectively, were found as best models for prediction of SSC at Minnesota river. The developed SGD-MLP-5 and SGD-RF-5 models with CC of 0.900 and 0.901, SI of 0.339 and 0.339, and WI of 0.945 and 0.946, respectively, gave accurate results at San Joaquin river. Through the application of SGD algorithm, the adaptive learning rate, epochs, rho, L1 and L2 were activated and presumed as 0.004, 10, 1, 0.000009 and 0, respectively. The ExpRectifier was considered as san activation operation due to its better efficiency in comparison with its alternatives for predicting SSC in SGD-MLP model. According to the results, the fifth scenario that incorporates SSCt–1, SSCt–2, Qt, Qt–1, and Qt–2 were found superior for SSC modeling in the studied rivers. The recommended hybrid algorithms based on GA and SGD optimization algorithms are proposed as practical tools for solving complex environmental problems.

Socio-Cultural Approaches to Tourism: A Research on the “Tourist” Notion of Young Turkish People

Abstract: Significance of tourism sector in Turkey is constantly expanding. Correspondingly the importance of the economic and socio-cultural impact of tourism also continues to develop. Because tourism draws tourists get into closer contact with the locals it has positive and negative effects on the destination. In general the aim of tourists is satisfying their expectations at the maximum degree during their stay. On the other side locals who live and work in the destination region have a primary role in welcoming them and satisfying the tourists’ needs and expectation. Turkish society is particularly well known for many generations as being very hospitable. Current research aims to reveal whether the young Turkish people sustain traditional “Turkish Hospitality” and to see their thoughts about tourists. The field research has been conducted on students of a foundation university located in Izmir and these young people’s point of view on tourists has been investigated by face to face interviews. It has been concluded that there is a weakening trend, nevertheless the notion of hospitality remains.

Exploring Topology Preservation of SOMs with a Graph Based Visualization

Abstract: The Self-Organizing Map (SOM), which projects a (high-dimensional) data manifold onto a lower-dimensional (usually 2-d) rigid lattice, is a commonly used manifold learning algorithm. However, a postprocessing --- that is often done by interactive visualization schemes --- is necessary to reveal the knowledge of the SOM. Thanks to the SOM property of producing (ideally) a topology preserving mapping, existing visualization schemes are often designed to show the similarities local to the lattice without considering the data topology. This can produce inadequate tools to investigate the detailed data structure and to what extent the topology is preserved during the SOM learning. A recent graph based SOM visualization, CONNvis [1], which exploits the underutilized knowledge of data topology, can be a suitable tool for such investigation. This paper discusses that CONNvis can represent the data topology on the SOM lattice despite the rigid grid structure, and hence can show the topology preservation of the SOM and the extent of topology violations.

The integrated network model of pipeline, sea and road distribution of petroleum product

Abstract: Nigeria ranks high among the community of oil producers both in the world. It is, therefore, paradoxical that Nigeria, with such profile in Organization of Petroleum Exporting Countries (OPEC) statistics finds it difficult to optimize its supply distribution while spending so much money on transportation and distribution. This paper thus reviews the petroleum product supply and distribution systems in the country. Thus, we develop a single period, single product deterministic mathematical model to effectively distribute the product to the end user through the most effective channel to the interest of the economy of the country. In our model, we first consider a perfect condition in the petroleum industry irrespective of the production crises and conflicts like pipeline vandalism, communal instability. We then consider different scnearios that presumes several breakdown cases in pipeline connection to anaylze the survivability of the network of petroleum distribution.