A comprehensive spectrum trading scheme based on market competition, reputation and buyer specific requirements
- Hassan, Md Rakib, Karmakar, Gour, Kamruzzaman, Joarder, Srinivasan, Bala
- Authors: Hassan, Md Rakib , Karmakar, Gour , Kamruzzaman, Joarder , Srinivasan, Bala
- Date: 2015
- Type: Text , Journal article
- Relation: Computer Networks Vol. 84, no. (2015), p. 17-31
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- Description: In the exclusive-use model of spectrum trading, cognitive radio devices or secondary users can buy spectrum resources from licensed users or primary users for a short or long period of time. Considering such spectrum access, a trading model is introduced where a buyer can select a set of candidate sellers based on their reputation and their offers in fulfilling its requirements, namely, offered signal quality, contract duration, coverage and bandwidth. Similarly, a seller can assess a buyer as a potential trading partner considering the buyer's reliability, which the seller can derive from the buyer's reputation and financial profile. In our scheme, seller reputation or buyer reliability can be either obtained from a reputation brokerage service, if one exists, or calculated using our model. Since in a competitive market, the price of a seller depends on that of other sellers, game theory is used to model the competition among multiple sellers. An optimization technique is used by a buyer to select the best seller(s) and optimize purchase to maximize its utility. This may result in buying from multiple sellers of certain amount of bandwidth from each, depending on price and meeting requirements and budget constraints. Stability of the model is analyzed and performance evaluation shows that it benefits sellers and buyers in terms of profit and throughput, respectively. © 2015 Elsevier B.V. All rights reserved.
- Authors: Hassan, Md Rakib , Karmakar, Gour , Kamruzzaman, Joarder , Srinivasan, Bala
- Date: 2015
- Type: Text , Journal article
- Relation: Computer Networks Vol. 84, no. (2015), p. 17-31
- Full Text:
- Reviewed:
- Description: In the exclusive-use model of spectrum trading, cognitive radio devices or secondary users can buy spectrum resources from licensed users or primary users for a short or long period of time. Considering such spectrum access, a trading model is introduced where a buyer can select a set of candidate sellers based on their reputation and their offers in fulfilling its requirements, namely, offered signal quality, contract duration, coverage and bandwidth. Similarly, a seller can assess a buyer as a potential trading partner considering the buyer's reliability, which the seller can derive from the buyer's reputation and financial profile. In our scheme, seller reputation or buyer reliability can be either obtained from a reputation brokerage service, if one exists, or calculated using our model. Since in a competitive market, the price of a seller depends on that of other sellers, game theory is used to model the competition among multiple sellers. An optimization technique is used by a buyer to select the best seller(s) and optimize purchase to maximize its utility. This may result in buying from multiple sellers of certain amount of bandwidth from each, depending on price and meeting requirements and budget constraints. Stability of the model is analyzed and performance evaluation shows that it benefits sellers and buyers in terms of profit and throughput, respectively. © 2015 Elsevier B.V. All rights reserved.
- Emery, Carolyn, Roos, Ewa, Verhagen, Evert, Finch, Caroline, Bennell, Kim, Spindler, Kurt, Kemp, Joanne, Lohmander, Stefan
- Authors: Emery, Carolyn , Roos, Ewa , Verhagen, Evert , Finch, Caroline , Bennell, Kim , Spindler, Kurt , Kemp, Joanne , Lohmander, Stefan
- Date: 2015
- Type: Text , Journal article
- Relation: Osteorthritis and Cartilage Vol. 23, no. 5 (2015), p. 815-825
- Full Text: false
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- Description: The risk of post-traumatic osteoarthritis (PTOA) substantially increases following joint injury. Research efforts should focus on investigating the efficacy of preventative strategies in high quality randomized controlled trials (RCT). The objective of these OARSI RCT recommendations is to inform the design, conduct and analytical approaches to RCTs evaluating the preventative effect of joint injury prevention strategies. Recommendations regarding the design, conduct, and reporting of RCTs evaluating injury prevention interventions were established based on the consensus of nine researchers internationally with expertise in epidemiology, injury prevention and/or osteoarthritis (OA). Input and resultant consensus was established through teleconference, face to face and email correspondence over a 1 year period. Recommendations for injury prevention RCTs include context specific considerations regarding the research question, research design, study participants, randomization, baseline characteristics, intervention, outcome measurement, analysis, implementation, cost evaluation, reporting and future considerations including the impact on development of PTOA. Methodological recommendations for injury prevention RCTs are critical to informing evidence-based practice and policy decisions in health care, public health and the community. Recommendations regarding the interpretation and conduct of injury prevention RCTs will inform the highest level of evidence in the field. These recommendations will facilitate between study comparisons to inform best practice in injury prevention that will have the greatest public health impact.
Nordic walking for overweight and obese people : a systematic review and meta-analysis
- Sanchez-Lastra, Miguel, Miller, Kyle, Martínez-Lemos, Rodolfo, Giráldez, Antón, Ayán, Carlos
- Authors: Sanchez-Lastra, Miguel , Miller, Kyle , Martínez-Lemos, Rodolfo , Giráldez, Antón , Ayán, Carlos
- Date: 2020
- Type: Text , Journal article
- Relation: Journal of Physical Activity and Health Vol. 17, no. 7 (2020), p. 762-772
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- Description: Background: Nordic walking (NW) is a potentially beneficial exercise strategy for overweight and obese people. To date, no reviews have synthesized the existing scientific evidence regarding the effects of NW on this population. This systematic review and meta-analysis aimed to identify the characteristics, methodological quality, and results of the investigations that have studied the effects of NW in overweight and obese individuals. Methods: Six electronic databases were searched up to June 2019 for studies that examined the effects of NW on people with a body mass index ≥ 25 kg/m2. The methodological quality of the included randomized controlled trials was retrieved from the physiotherapy evidence database or evaluated using the physiotherapy evidence database scale. Results: Twelve studies were included in the review. The investigations were mostly good-to-fair methodological quality. NW groups had a significant improvement on parameters such as fasting plasma glucose, abdominal adiposity, and body fat compared with the baseline, but no significant improvements were found when compared with control groups. Conclusions: NW can potentially lead to improvements in parameters related to major health outcomes in overweight and obese people. The lack of control for confounding variables in the analyzed studies prevents further elaboration on its potential benefits. © 2020 Human Kinetics, Inc.
- Authors: Sanchez-Lastra, Miguel , Miller, Kyle , Martínez-Lemos, Rodolfo , Giráldez, Antón , Ayán, Carlos
- Date: 2020
- Type: Text , Journal article
- Relation: Journal of Physical Activity and Health Vol. 17, no. 7 (2020), p. 762-772
- Full Text:
- Reviewed:
- Description: Background: Nordic walking (NW) is a potentially beneficial exercise strategy for overweight and obese people. To date, no reviews have synthesized the existing scientific evidence regarding the effects of NW on this population. This systematic review and meta-analysis aimed to identify the characteristics, methodological quality, and results of the investigations that have studied the effects of NW in overweight and obese individuals. Methods: Six electronic databases were searched up to June 2019 for studies that examined the effects of NW on people with a body mass index ≥ 25 kg/m2. The methodological quality of the included randomized controlled trials was retrieved from the physiotherapy evidence database or evaluated using the physiotherapy evidence database scale. Results: Twelve studies were included in the review. The investigations were mostly good-to-fair methodological quality. NW groups had a significant improvement on parameters such as fasting plasma glucose, abdominal adiposity, and body fat compared with the baseline, but no significant improvements were found when compared with control groups. Conclusions: NW can potentially lead to improvements in parameters related to major health outcomes in overweight and obese people. The lack of control for confounding variables in the analyzed studies prevents further elaboration on its potential benefits. © 2020 Human Kinetics, Inc.
XPloreRank: exploring XML data via you may also like queries
- Naseriparsa, Mehdi, Liu, Chengfei, Islam, Md Saiful, Zhou, Rui
- Authors: Naseriparsa, Mehdi , Liu, Chengfei , Islam, Md Saiful , Zhou, Rui
- Date: 2019
- Type: Text , Journal article
- Relation: World Wide Web Vol. 22, no. 4 (2019), p. 1727-1750
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- Description: In many cases, users are not familiar with their exact information needs while searching complicated data sources. This lack of understanding may cause the users to feel dissatisfaction when the system retrieves insufficient results after they issue queries. However, using their original query results, we may recommend additional queries which are highly relevant to the original query. This paper presents XPloreRank to recommend top-l highly relevant keyword queries called “You May Also Like” (YMAL) queries to the users in XML keyword search. To generate such queries, we firstly analyze the original keyword query results content and construct a weighted co-occurring keyword graph. Then, we generate the YMAL queries by traversing the co-occurring keyword graph and rank them based on the following correlation aspects: (a) external correlation, which measures the similarity of the YMAL query to the original query and (b) internal correlation, which measures the capability of the YMAL query keywords in producing meaningful results with respect to the data source. Due to the complexity of generating YMAL queries, we propose a novel A* search-based technique to generate top-l YMAL queries efficiently. We also present a greedy-based approximation for it to improve the performance further. Extensive experiments verify the effectiveness and efficiency of our approach. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
- Authors: Naseriparsa, Mehdi , Liu, Chengfei , Islam, Md Saiful , Zhou, Rui
- Date: 2019
- Type: Text , Journal article
- Relation: World Wide Web Vol. 22, no. 4 (2019), p. 1727-1750
- Full Text:
- Reviewed:
- Description: In many cases, users are not familiar with their exact information needs while searching complicated data sources. This lack of understanding may cause the users to feel dissatisfaction when the system retrieves insufficient results after they issue queries. However, using their original query results, we may recommend additional queries which are highly relevant to the original query. This paper presents XPloreRank to recommend top-l highly relevant keyword queries called “You May Also Like” (YMAL) queries to the users in XML keyword search. To generate such queries, we firstly analyze the original keyword query results content and construct a weighted co-occurring keyword graph. Then, we generate the YMAL queries by traversing the co-occurring keyword graph and rank them based on the following correlation aspects: (a) external correlation, which measures the similarity of the YMAL query to the original query and (b) internal correlation, which measures the capability of the YMAL query keywords in producing meaningful results with respect to the data source. Due to the complexity of generating YMAL queries, we propose a novel A* search-based technique to generate top-l YMAL queries efficiently. We also present a greedy-based approximation for it to improve the performance further. Extensive experiments verify the effectiveness and efficiency of our approach. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
XSnippets : exploring semi-structured data via snippets
- Naseriparsa, Mehdi, Islam, Md Saiful, Liu, Chengfei, Chen, Lu
- Authors: Naseriparsa, Mehdi , Islam, Md Saiful , Liu, Chengfei , Chen, Lu
- Date: 2019
- Type: Text , Journal article
- Relation: Data and Knowledge Engineering Vol. 124, no. (2019), p.
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- Description: Users are usually not familiar with the content and structure of the data when they explore the data source. However, to improve the exploration usability, they need some primary hints about the data source. These hints should represent the overall picture of the data source and include the trending issues that can be extracted from the query log. In this paper, we propose a two-phase interactive exploratory search framework for the clueless users that exploits the snippets for conducting the search on the XML data. In the first phase, we present the primary snippets that are generated from the keywords of the query log to start the exploration. To retrieve the primary snippets, we develop an A* search-based technique on the keyword space of the query log. To improve the performance of computations, we store the primary snippet computations in an index data structure to reuse it for the next steps. In the second phase, we exploit the co-occurring content of the snippets to generate more specific snippets with the user interaction. To expedite the performance, we design two pruning techniques called inter-snippet and intra-snippet pruning to stop unnecessary computations. Finally, we discuss a termination condition that checks the cardinality of the snippets to stop the interactive phase and present the final Top-l snippets to the user. Our experiments on real datasets verify the effectiveness and efficiency of the proposed framework. © 2019 Elsevier B.V.
- Authors: Naseriparsa, Mehdi , Islam, Md Saiful , Liu, Chengfei , Chen, Lu
- Date: 2019
- Type: Text , Journal article
- Relation: Data and Knowledge Engineering Vol. 124, no. (2019), p.
- Full Text:
- Reviewed:
- Description: Users are usually not familiar with the content and structure of the data when they explore the data source. However, to improve the exploration usability, they need some primary hints about the data source. These hints should represent the overall picture of the data source and include the trending issues that can be extracted from the query log. In this paper, we propose a two-phase interactive exploratory search framework for the clueless users that exploits the snippets for conducting the search on the XML data. In the first phase, we present the primary snippets that are generated from the keywords of the query log to start the exploration. To retrieve the primary snippets, we develop an A* search-based technique on the keyword space of the query log. To improve the performance of computations, we store the primary snippet computations in an index data structure to reuse it for the next steps. In the second phase, we exploit the co-occurring content of the snippets to generate more specific snippets with the user interaction. To expedite the performance, we design two pruning techniques called inter-snippet and intra-snippet pruning to stop unnecessary computations. Finally, we discuss a termination condition that checks the cardinality of the snippets to stop the interactive phase and present the final Top-l snippets to the user. Our experiments on real datasets verify the effectiveness and efficiency of the proposed framework. © 2019 Elsevier B.V.
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