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To achieve improved availability and performance, often, local copies of remote data from autonomous sources are maintained. Web search engines are the primary examples of such services. Increasingly, these services are utilizing ...
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To achieve improved availability and performance, often, local copies of remote data from autonomous sources are maintained. Web search engines are the primary examples of such services. Increasingly, these services are utilizing the Semantic Web as it is often envisioned as a machine-interpretable web. In order to keep the local repositories current, it is essential to synchronize their content with that of their original sources. Change detection is the first step to accomplish this. It is essential to have efficient change detection mechanisms as the size of the local repositories is often very large. In this paper, we present an approach that exploits the semantic relationships among the concepts in guiding the change detection process. Given changes to some seed instances, a reasoning engine fires a set of pre-defined rules to characterize the profile of the changed target instances. In addition to change detection, our proposed semantics-based approach of utilizing semantic associations can be utilized in other applications such as guiding information discovery for agents, consistency maintenance among distributed information sources, among others.
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The food safety standard ontology is the schema layer of top-bottom building method for constructing the food safety knowledge graph, which can effectively ensure the professionalism and effectiveness of the knowledge graph. Howev...
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The food safety standard ontology is the schema layer of top-bottom building method for constructing the food safety knowledge graph, which can effectively ensure the professionalism and effectiveness of the knowledge graph. However, there are few relevant research in recent literature, which also restricts the application of knowledge graph in the food safety field. In order to solve this problem, this paper proposes the construction method of food safety standard ontology based on the national food safety standards. Firstly, we built the class framework of the food safety standards according to the seven steps of ontology construction, and then entities, attributes and relations between entities are extracted from the national food safety standards by employing the rule-based knowledge extraction algorithm. Finally, we import those entities, attributes and relations into the class framework to complete the ontology. According to the experimental results of our entity mapping, the food safety standard ontology can describe the mainly important concepts, terms, operation process and their relation in the standards. So it will effectively support the construction and integration of knowledge graph.
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Patterning on polymer thin film surface by excimer laser irradiation was carried out by two means. One was selective removal of metal thin film from a metal-coated polytetrafluoloethylene (PTFE) film surface by laser ablation. Ano...
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Patterning on polymer thin film surface by excimer laser irradiation was carried out by two means. One was selective removal of metal thin film from a metal-coated polytetrafluoloethylene (PTFE) film surface by laser ablation. Another direct irradiation on a clean polyimide surface. The polytetrafluoloethylene film patterned by the first means was used as sensing electrode of electrochemical gas sensor with improvement of both the sensitivity by 5 times and single-to-noise ratio by 2 times comparing with that fabricated by conventional technique. Patterning on a polyimide film surface by the second means resulted in the increase of surface conductivity to about 10~0 Ω~(-1) cm~(-1). Such surface conductivity made it possible for electrochemical deposition on the irradiated polyimide surface and then a catalytic layer was prepared on the polyimide film surface. The feasibility of using such catalytic layer with polyimide film as the sensing electrode of electrochemical gas sensor was demonstrated.
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摘要 :
Patterning on polymer thin film surface by excimer laser irradiation was carried out by two means. One was selective removal of metal thin film from a metal-coated polytetrafluoloethylene (PTFE) film surface by laser ablation. Ano...
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Patterning on polymer thin film surface by excimer laser irradiation was carried out by two means. One was selective removal of metal thin film from a metal-coated polytetrafluoloethylene (PTFE) film surface by laser ablation. Another directirradiation on a clean polyimide surface. The polytetrafluoloethylene film patterned by the first means was used as sensing electrode of electrochemical gas sensor with improvement of both the sensitivity by 5 times and single-to-noise ratio by 2 timescomparing with that fabricated by conventional technique. Patterning on a polyimide film surface by the second means resulted in the increase of surface conductivity to about 10{sup}0Ω{sup}(-1)cm{sup}(-1). Such surface conductivity made it possible forelectrochemical deposition on the irradiated polyimide surface and then a catalytic layer was prepared on the polyimide film surface. The feasibility of using such catalytic layer with polyimide film as the sensing electrode of electrochemical gas sensorwas demonstrated.
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In this paper, we present the principles about the construction of high order schemes. Research works show that the second order scheme based on the principles is firee of oscillations. The third and higher order schemes are only ...
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In this paper, we present the principles about the construction of high order schemes. Research works show that the second order scheme based on the principles is firee of oscillations. The third and higher order schemes are only of tiny oscillations in the region of shock wave and have higher resolution rate in the rest of the field. We also discuss the ways to depress the tiny oscillations and give applications using the high order schemes.
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The Semantic Web is envisioned as the next generation web in which data instances are enriched with metadata defined in ontologies to describe the meaning of its instances. In this paper, we present an approach that exploits ontol...
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The Semantic Web is envisioned as the next generation web in which data instances are enriched with metadata defined in ontologies to describe the meaning of its instances. In this paper, we present an approach that exploits ontologies in guiding the change detection to their data instances. Inference rules are identified based on the semantic relationships among concepts, properties and instances as well as their change behaviors. Starting with changes to some seed instances, a reasoning engine is designed to fire the pre-defined rule set and act on ontologies to project some semantically associated concepts as target concepts. Certain instances of these target concepts are further selected as target instances, which have a high likelihood of having changed. Our approach is specifically oriented toward the Semantic Web, thus it has intelligence to exploit the semantic associations among data instances and make smart decisions.
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摘要 :
The Semantic Web is envisioned as the next generation web in which data instances are enriched with metadata defined in ontologies to describe the meaning of its instances. In this paper, we present an approach that exploits ontol...
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The Semantic Web is envisioned as the next generation web in which data instances are enriched with metadata defined in ontologies to describe the meaning of its instances. In this paper, we present an approach that exploits ontologies in guiding the change detection to their data instances. Inference rules are identified based on the semantic relationships among concepts, properties and instances as well as their change behaviors. Starting with changes to some seed instances, a reasoning engine is designed to fire the pre-defined rule set and act on ontologies to project some semantically associated concepts as target concepts. Certain instances of these target concepts are further selected as target instances, which have a high likelihood of having changed. Our approach is specifically oriented toward the Semantic Web, thus it has intelligence to exploit the semantic associations among data instances and make smart decisions.
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Flood is one of the more catastrophic natural disasters, which is also associated with damage to infrastructures, human suffering, and economic losses. This study develops a remotely controlled autonomous method for in-network sto...
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Flood is one of the more catastrophic natural disasters, which is also associated with damage to infrastructures, human suffering, and economic losses. This study develops a remotely controlled autonomous method for in-network storage systems in remote locations to mitigate floods. The storage systems considered include wetlands, detention ponds, and reservoirs. The outlet structure types for each storage system include a siphon system and a conventional outlet structure with controlled gates. The proposed architecture collects information about the deployed devices in the field and can receive orders from an operator to open and close outlet gates. The architecture comprises five layers: user-end, a server with a decision support system (DSS) and integrated control software, remote communication, programming logic controller (PLC) system, and hardware/sensors deployed in the field. The operation of two siphon systems in a flume controlled by the proposed integrated software is tested in the lab.
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Power scaling and beam divergence compression of 980 nm bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) are presented in this paper. First, the relationships among the reflectivity of the n-doped distributed Bragg...
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Power scaling and beam divergence compression of 980 nm bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) are presented in this paper. First, the relationships among the reflectivity of the n-doped distributed Bragg reflector, threshold current, and output power were analyzed, and the n-DBR reflectivity was optimized to achieve higher slope efficiency in a relatively low threshold current. Second, the influence of the p-contact on the current density distribution inside the active region was analyzed using the three-dimensional finite-element method. Uniform current distribution was achieved by optimizing the diameter of the p-contact, and a consequent improvement in beam divergence was observed. A low divergence of 5.4° was obtained for a single device with continuous-wave (CW) of 1.46 W at room temperature. The 8×8 VCSEL array showed a divergence angle of 10.2° at 4A. This array afforded a CW output power of 1.95 W under an injected current of 4 A and a pulse output power of 115 W under a pulse drive current of 130 A, a pulse width of 100 ns, and a repetition frequency of 100 Hz. VCSEL array chips were packaged in series to form a "quasi-array" to further increase the output power. This series achieved a peak output power of 475 W under a pulse drive current of 120 A.
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Power scaling and beam divergence compression of 980 nm bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) are presented in this paper. First, the relationships among the reflectivity of the n-doped distributed Bragg...
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Power scaling and beam divergence compression of 980 nm bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) are presented in this paper. First, the relationships among the reflectivity of the n-doped distributed Bragg reflector, threshold current, and output power were analyzed, and the n-DBR reflectivity was optimized to achieve higher slope efficiency in a relatively low threshold current. Second, the influence of the p-contact on the current density distribution inside the active region was analyzed using the three-dimensional finite-element method. Uniform current distribution was achieved by optimizing the diameter of the p-contact, and a consequent improvement in beam divergence was observed. A low divergence of 5.4° was obtained for a single device with continuous-wave (CW) of 1.46 W at room temperature. The 8×8 VCSEL array showed a divergence angle of 10.2° at 4A. This array afforded a CW output power of 1.95 W under an injected current of 4 A and a pulse output power of 115 W under a pulse drive current of 130 A, a pulse width of 100 ns, and a repetition frequency of 100 Hz. VCSEL array chips were packaged in series to form a "quasi-array" to further increase the output power. This series achieved a peak output power of 475 W under a pulse drive current of 120 A.
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