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Papers by Onur Tosun Tosun

Research paper thumbnail of Tag Suggestr: Automatic Photo Tag Expansion Using Visual Information for Photo Sharing Websites

In this paper, we propose an automatic photo tag expansion system for the community photo collect... more In this paper, we propose an automatic photo tag expansion system for the community photo collections, such as Flickr. Our aim is to suggest relevant tags for a target photograph uploaded to the system by a user, by incorporating the visual and textual cues from other related photographs. As the first step, the system requires the user to add only a few initial tags for each uploaded photo. These initial tags are used to retrieve related photos including the same tags in their tag lists. Then the set of candidate tags collected from a large pool of photos is weighted according to the similarity of the target photo to the retrieved photo including the tag. Finally, the tags in the highest rankings are used to automatically expand the tags of the target photo. The experimental results on Flickr photos show that, the use of visual similarity of semantically relevant photos to recommend tags improves the quality of suggested tags compared to only text-based systems.

Research paper thumbnail of ANP application for evaluating Turkish mobile communication operators

Journal of Global Optimization, 2008

The proposed decision model, based on Analytic Network Process (ANP), has been developed in order... more The proposed decision model, based on Analytic Network Process (ANP), has been developed in order to determine the dynamics of the Global System for Mobile Communications (GSM) market. In accordance with the sequence of ANP, first of all, the problem was structured and modeled. At the next step, a quantitative analysis was conducted with the customers in order to assess the importance of the related factors and forecast the market shares of the Turkish mobile communication operators. The forecasted market share values were compared with actual ones for the validation of the decision model. The assessed importance of the factors in a valid model would be a potential competitive advantage for the mobile operators.

Research paper thumbnail of First record of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) infection in larvae and pupae of Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) from Turkey

Journal of Invertebrate Pathology, 2009

The predator beetle Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) is one of the most impo... more The predator beetle Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) is one of the most important biological control agents, mass-bred and used to suppress populations of an important pest: the great spruce bark beetle, Dendroctonus micans. The achlorophyllous alga Helicosporidium sp. was first discovered in the pest. Later it was also found in the predator, but only in the adults. In this study, the pathogenic alga Helicosporidium sp. was discovered in larvae and early pupae of R. grandis for the first time. The morphological characteristics of the pathogenic alga were revealed by light and electron microscopy. Infection rates of Helicosporidium sp. in the larvae and pupae of R. grandis were 23.5% and 6.25%, respectively.

Research paper thumbnail of Distribution and occurrence of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis G yll. (Coleoptera: Rhizophagidae)-rearing laboratories

Folia Microbiologica, 2011

The distribution and occurrence of the insect pathogenic algae Helicosporidium sp. (Chlorophyta: ... more The distribution and occurrence of the insect pathogenic algae Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis (Coleoptera: Rhizophagidae)-rearing laboratories were studied and reported here for the first time. The insect pathogenic alga Helicosporidium sp. infection was observed in all R. grandis-rearing laboratories. The infection rate reached more than 20% which is significant among the samples in some R. grandis-rearing laboratories. The infection rates of the examined beetles showed noticeable differences between localities and years. There was no significant difference in the infection levels of male and female beetles. These results showed that Helicosporidium sp. is one of the factors that decrease efficiency of the R. grandis-rearing laboratories.

Research paper thumbnail of An attractive agro-industrial by-product in environmental cleanup: Dye biosorption potential of untreated olive pomace

Journal of Hazardous Materials, 2009

This research deals with the evaluation of highly available and cost effective waste biomass of o... more This research deals with the evaluation of highly available and cost effective waste biomass of olive pomace for the removal of reactive textile dye, RR198 from aqueous medium and a real effluent. The experiments were conducted to assess the effects of process variables such as initial pH, biosorbent dosage, contact time, temperature and ionic strength. The results showed that the highest dye biosorption capacity was found at pH 2 and the needed time to reach the biosorption equilibrium was 40 min with a biosorbent concentration of 3.0 g L −1 . The sorption kinetics of dye was best described by the pseudosecond-order kinetic model. The equilibrium biosorption data were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models and the results from the isotherm studies showed that the RR198 biosorption process occurred on a homogenous surface of the biosorbent. The waste biomass of olive oil industry displayed biosorption capacities ranging from 6.05 × 10 −5 to 1.08 × 10 −4 mol g −1 at different temperatures. The negative values of G • and the positive value of H • suggest that the biosorption process for RR198 was spontaneous and endothermic. Dye-biosorbent interactions were examined by FTIR and SEM analysis. Finally, high biosorption yield of olive waste for the removal of RR198 dye from real wastewater makes it possible that the olive pomace could be applied widely in wastewater treatment as biosorbent taking into account that no pretreatment on the solid residue is carried out.

Research paper thumbnail of Occurrence of the Pathogens and Parasites of Phyllotreta undulata (Coleoptera: Chrysomelidae) in Turkey

The pathogens and parasites of Pyllotreta undulata Kutschera (Coleoptera: Chrysomelidae) collecte... more The pathogens and parasites of Pyllotreta undulata Kutschera (Coleoptera: Chrysomelidae) collected from 5 localities in the Black Sea region of Turkey were investigated. Four different types of pathogens and parasites were recorded in adults of P. undulata: gregarine, microsporidium, and 2 nematodes, namely 1 Howardula species and 1 Hexamermis species. Gregarine and Howardula were the most common pathogen and parasite in P. undulata populations. There is the first record of a Hexamermis (Nematoda: Mermithidae) parasite from P. undulata in Turkey.

Research paper thumbnail of Data Salmon: A Greedy Mobile Basestation Protocol for Efficient Data Collection in Wireless Sensor Networks

Our work addresses the spatiotemporally varying nature of data traffic in environmental monitorin... more Our work addresses the spatiotemporally varying nature of data traffic in environmental monitoring and surveillance applications. By employing a network-controlled mobile basestation (MB), we present a simple energy-efficient data collection protocol for wireless sensor networks (WSNs). In contrast to the existing MB-based solutions where WSN nodes buffer data passively until visited by an MB, our protocol maintains an always-on multihop connectivity to the MB by means of an efficient distributed tracking mechanism. This allows the nodes to forward their data in a timely fashion, avoiding latencies due to long-term buffering. Our protocol progressively relocates the MB closer to the regions that produce higher data rates and reduces the average weighted multihop traffic, enabling energy savings. Using the convexity of the cost function, we prove that our local and greedy protocol is in fact optimal.

Research paper thumbnail of General gynecology

Archives of Gynecology and Obstetrics, 2005

Research paper thumbnail of Effects of iloprost and piracetam in spinal cord ischemia–reperfusion injury in the rabbit

Research paper thumbnail of Tag Suggestr: Automatic Photo Tag Expansion Using Visual Information for Photo Sharing Websites

In this paper, we propose an automatic photo tag expansion system for the community photo collect... more In this paper, we propose an automatic photo tag expansion system for the community photo collections, such as Flickr. Our aim is to suggest relevant tags for a target photograph uploaded to the system by a user, by incorporating the visual and textual cues from other related photographs. As the first step, the system requires the user to add only a few initial tags for each uploaded photo. These initial tags are used to retrieve related photos including the same tags in their tag lists. Then the set of candidate tags collected from a large pool of photos is weighted according to the similarity of the target photo to the retrieved photo including the tag. Finally, the tags in the highest rankings are used to automatically expand the tags of the target photo. The experimental results on Flickr photos show that, the use of visual similarity of semantically relevant photos to recommend tags improves the quality of suggested tags compared to only text-based systems.

Research paper thumbnail of ANP application for evaluating Turkish mobile communication operators

Journal of Global Optimization, 2008

The proposed decision model, based on Analytic Network Process (ANP), has been developed in order... more The proposed decision model, based on Analytic Network Process (ANP), has been developed in order to determine the dynamics of the Global System for Mobile Communications (GSM) market. In accordance with the sequence of ANP, first of all, the problem was structured and modeled. At the next step, a quantitative analysis was conducted with the customers in order to assess the importance of the related factors and forecast the market shares of the Turkish mobile communication operators. The forecasted market share values were compared with actual ones for the validation of the decision model. The assessed importance of the factors in a valid model would be a potential competitive advantage for the mobile operators.

Research paper thumbnail of First record of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) infection in larvae and pupae of Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) from Turkey

Journal of Invertebrate Pathology, 2009

The predator beetle Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) is one of the most impo... more The predator beetle Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) is one of the most important biological control agents, mass-bred and used to suppress populations of an important pest: the great spruce bark beetle, Dendroctonus micans. The achlorophyllous alga Helicosporidium sp. was first discovered in the pest. Later it was also found in the predator, but only in the adults. In this study, the pathogenic alga Helicosporidium sp. was discovered in larvae and early pupae of R. grandis for the first time. The morphological characteristics of the pathogenic alga were revealed by light and electron microscopy. Infection rates of Helicosporidium sp. in the larvae and pupae of R. grandis were 23.5% and 6.25%, respectively.

Research paper thumbnail of Distribution and occurrence of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis G yll. (Coleoptera: Rhizophagidae)-rearing laboratories

Folia Microbiologica, 2011

The distribution and occurrence of the insect pathogenic algae Helicosporidium sp. (Chlorophyta: ... more The distribution and occurrence of the insect pathogenic algae Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis (Coleoptera: Rhizophagidae)-rearing laboratories were studied and reported here for the first time. The insect pathogenic alga Helicosporidium sp. infection was observed in all R. grandis-rearing laboratories. The infection rate reached more than 20% which is significant among the samples in some R. grandis-rearing laboratories. The infection rates of the examined beetles showed noticeable differences between localities and years. There was no significant difference in the infection levels of male and female beetles. These results showed that Helicosporidium sp. is one of the factors that decrease efficiency of the R. grandis-rearing laboratories.

Research paper thumbnail of An attractive agro-industrial by-product in environmental cleanup: Dye biosorption potential of untreated olive pomace

Journal of Hazardous Materials, 2009

This research deals with the evaluation of highly available and cost effective waste biomass of o... more This research deals with the evaluation of highly available and cost effective waste biomass of olive pomace for the removal of reactive textile dye, RR198 from aqueous medium and a real effluent. The experiments were conducted to assess the effects of process variables such as initial pH, biosorbent dosage, contact time, temperature and ionic strength. The results showed that the highest dye biosorption capacity was found at pH 2 and the needed time to reach the biosorption equilibrium was 40 min with a biosorbent concentration of 3.0 g L −1 . The sorption kinetics of dye was best described by the pseudosecond-order kinetic model. The equilibrium biosorption data were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models and the results from the isotherm studies showed that the RR198 biosorption process occurred on a homogenous surface of the biosorbent. The waste biomass of olive oil industry displayed biosorption capacities ranging from 6.05 × 10 −5 to 1.08 × 10 −4 mol g −1 at different temperatures. The negative values of G • and the positive value of H • suggest that the biosorption process for RR198 was spontaneous and endothermic. Dye-biosorbent interactions were examined by FTIR and SEM analysis. Finally, high biosorption yield of olive waste for the removal of RR198 dye from real wastewater makes it possible that the olive pomace could be applied widely in wastewater treatment as biosorbent taking into account that no pretreatment on the solid residue is carried out.

Research paper thumbnail of Occurrence of the Pathogens and Parasites of Phyllotreta undulata (Coleoptera: Chrysomelidae) in Turkey

The pathogens and parasites of Pyllotreta undulata Kutschera (Coleoptera: Chrysomelidae) collecte... more The pathogens and parasites of Pyllotreta undulata Kutschera (Coleoptera: Chrysomelidae) collected from 5 localities in the Black Sea region of Turkey were investigated. Four different types of pathogens and parasites were recorded in adults of P. undulata: gregarine, microsporidium, and 2 nematodes, namely 1 Howardula species and 1 Hexamermis species. Gregarine and Howardula were the most common pathogen and parasite in P. undulata populations. There is the first record of a Hexamermis (Nematoda: Mermithidae) parasite from P. undulata in Turkey.

Research paper thumbnail of Data Salmon: A Greedy Mobile Basestation Protocol for Efficient Data Collection in Wireless Sensor Networks

Our work addresses the spatiotemporally varying nature of data traffic in environmental monitorin... more Our work addresses the spatiotemporally varying nature of data traffic in environmental monitoring and surveillance applications. By employing a network-controlled mobile basestation (MB), we present a simple energy-efficient data collection protocol for wireless sensor networks (WSNs). In contrast to the existing MB-based solutions where WSN nodes buffer data passively until visited by an MB, our protocol maintains an always-on multihop connectivity to the MB by means of an efficient distributed tracking mechanism. This allows the nodes to forward their data in a timely fashion, avoiding latencies due to long-term buffering. Our protocol progressively relocates the MB closer to the regions that produce higher data rates and reduces the average weighted multihop traffic, enabling energy savings. Using the convexity of the cost function, we prove that our local and greedy protocol is in fact optimal.

Research paper thumbnail of General gynecology

Archives of Gynecology and Obstetrics, 2005

Research paper thumbnail of Effects of iloprost and piracetam in spinal cord ischemia–reperfusion injury in the rabbit