Spectrum auction is an important approach of spectrum distribution in cognitive radio networks. However, a single secondary user(SU) probably can't afford the price of spectrum. Multiple SUs grouping together to p...Spectrum auction is an important approach of spectrum distribution in cognitive radio networks. However, a single secondary user(SU) probably can't afford the price of spectrum. Multiple SUs grouping together to participate in the auction as a whole is helpful to increase purchasing power. However, SUs could suffer from a new group cheating problem, i.e., parts of users conspire to manipulate the auction by submitting untruthful bids. Existing auction mechanisms were mainly designed to be strategy-proof only for individual user and can't deal with group cheating. In this paper, a novel spectrum auction mechanism called COSTAG(COst Sharing based Truthful Auction with Group-buying) is proposed to address the group cheating problem. COSTAG consists of a grouping rule to perform grouping and a payment rule to determine the market-clearing price in the spectrum auction. Different from single-echelon pricing approach employed in existing works, a multi-echelon pricing strategy is designed to increase the transaction rate and optimize social profit for the auction. Comprehensive theoretical analysis shows that COSTAG can satisfy the crucial economic robustness properties, both individual and group truthfulness. Simulations demonstrate that comparing with existing works, COSTAG can improve the system performance significantly.展开更多
Purpose： To compare the efficacy of quadratus femoris muscle pedicle bone flap transplantation combined with hollow compression screw fixation versus AO hollow compression screw fixation in the treatment of femoral n...Purpose： To compare the efficacy of quadratus femoris muscle pedicle bone flap transplantation combined with hollow compression screw fixation versus AO hollow compression screw fixation in the treatment of femoral neck fracture for Chinese young and middle-aged patients. Methods： Case-controlled studies （CCTs） were used to compare the two operative methods in the treatment of femoral neck fractures. Data were retrieved from the Cochrane Library, Pubmed Database, CNKI, Chinese Biomedical Database. Wanfang Data published during the period of January 2005 to December 2014. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical Software Revman S.0 was used for data-analysis. Results： Eight articles were included in the meta-analysis. The results showed that there was statistical significance in the rate of fracture healing [OR = 5.43, 95% CI （2.89, 10.20）, p 〈 0.05], the rate of good function of hip joint [OR=5.12, 95% CI （3.21, 8.17）, p 〈 0.05], the rate of femoral head necrosis [OR = 4.21, 95% CI （2.02, 8.76）, p 〈 0.05], the time of fracture healing [WMD = -46.85, 95% CI （-65.13, -28.56）, p 〈 0.05] between the two groups. Conclusions： For the treatment of femoral neck fractures, the transplantation of quadratus femoris muscle pedicle bone flap combined with hollow compression screw; fixation is superior to the AO hollow compression screw fixation in terms of the rate; of fracture healing, the rate of good function of hip joint, the rate of femoral head： necrosis and the time of fracture healing.展开更多
This paper studies one managerial decision problem of the auction sites： how to combine penalties with commissions？ It is shown that when there exists secondary auction market, the auction whose penalty is a linear ...This paper studies one managerial decision problem of the auction sites： how to combine penalties with commissions？ It is shown that when there exists secondary auction market, the auction whose penalty is a linear function of the seller＇s commission will be more efficient than the auction with only commissions but no penalties. It has also been proven that using this strategy can maximize the expected revenue for the seller, the auction site and their total expected revenues.展开更多
Purpose： To evaluate the role of immediate and definitive management of Gustilo type Ⅲ A/B tibia fractures with intramedullary nailing and fasciocutaneous flap. Methods： From August 2010 to July 2012, 22 patients w...Purpose： To evaluate the role of immediate and definitive management of Gustilo type Ⅲ A/B tibia fractures with intramedullary nailing and fasciocutaneous flap. Methods： From August 2010 to July 2012, 22 patients with Gustilo Grade Ⅲ A/B tibia fractures were managed with a single stage treatment of ipsilateral fasciocutaneous flap ＆ reamed intramedullary nailing and were included in the study. The severity of the injury was calculated with Ganga Hospital injury severity score. Results： The mean age of patients was 41 years and the follow-up time ranged from six months to one year. Among the 22 patients, 73% were type Ⅲ B fractures with upper leg involved in 55% of them. The time interval from injury to completion of surgery was 8 14 h. The incidence of bone infection requiring secondary procedure was 9%; the major and minor soft tissue complication rate was 9% and 14% respectively. The limb salvage rate was 100%. Conclusion： Multidisciplinary management of severe lower limb trauma is important and provides good outcomes, lntramedullary nailing and immediate flap fixation can achieve early bone union and good soft tissue coverage, leading to good outcomes in patient with Grade Ⅲ A ＆ B tibia fractures.展开更多
In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects a...In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects are sold sequentially and each buyer's valuation for the second object is k times that for the first one,and the true value of k is sellers' private information.The authors identify three factors which affect sellers' revelation strategies: The market's competition intensity which is characterized by the number of buyers,buyers' prior information about the second object,and the difference degree between two objects which is characterized by k.The authors give not only conditions under which revealing information about the second object in advance benefits the seller,but also the optimal releasing amount of information in the market with two sellers and one seller,respectively.展开更多
基金partially supported by the National Science Foundation of China (No. 61070211, No. 61003304, No 61501482 and No 61070201)Equipment research foundation (No.6140134040216)the Ph.D. Programs Foundation of Ministry of Education of China (No. 20114307120003)
文摘Spectrum auction is an important approach of spectrum distribution in cognitive radio networks. However, a single secondary user(SU) probably can't afford the price of spectrum. Multiple SUs grouping together to participate in the auction as a whole is helpful to increase purchasing power. However, SUs could suffer from a new group cheating problem, i.e., parts of users conspire to manipulate the auction by submitting untruthful bids. Existing auction mechanisms were mainly designed to be strategy-proof only for individual user and can't deal with group cheating. In this paper, a novel spectrum auction mechanism called COSTAG(COst Sharing based Truthful Auction with Group-buying) is proposed to address the group cheating problem. COSTAG consists of a grouping rule to perform grouping and a payment rule to determine the market-clearing price in the spectrum auction. Different from single-echelon pricing approach employed in existing works, a multi-echelon pricing strategy is designed to increase the transaction rate and optimize social profit for the auction. Comprehensive theoretical analysis shows that COSTAG can satisfy the crucial economic robustness properties, both individual and group truthfulness. Simulations demonstrate that comparing with existing works, COSTAG can improve the system performance significantly.
基金National Natural Science Foundation of China （81572098） Natural Science Foundation of Shanxi Province of China （2008012011-3, 201701D121161）.
文摘Purpose： To compare the efficacy of quadratus femoris muscle pedicle bone flap transplantation combined with hollow compression screw fixation versus AO hollow compression screw fixation in the treatment of femoral neck fracture for Chinese young and middle-aged patients. Methods： Case-controlled studies （CCTs） were used to compare the two operative methods in the treatment of femoral neck fractures. Data were retrieved from the Cochrane Library, Pubmed Database, CNKI, Chinese Biomedical Database. Wanfang Data published during the period of January 2005 to December 2014. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical Software Revman S.0 was used for data-analysis. Results： Eight articles were included in the meta-analysis. The results showed that there was statistical significance in the rate of fracture healing [OR = 5.43, 95% CI （2.89, 10.20）, p 〈 0.05], the rate of good function of hip joint [OR=5.12, 95% CI （3.21, 8.17）, p 〈 0.05], the rate of femoral head necrosis [OR = 4.21, 95% CI （2.02, 8.76）, p 〈 0.05], the time of fracture healing [WMD = -46.85, 95% CI （-65.13, -28.56）, p 〈 0.05] between the two groups. Conclusions： For the treatment of femoral neck fractures, the transplantation of quadratus femoris muscle pedicle bone flap combined with hollow compression screw; fixation is superior to the AO hollow compression screw fixation in terms of the rate; of fracture healing, the rate of good function of hip joint, the rate of femoral head： necrosis and the time of fracture healing.
基金The research was supported by NNSF of China and RGC of Hong Kong Joint Research Scheme(Project No.N_CityU103/02)also supported by National Natural Science Foundation of China(Project No. 70401004)
文摘This paper studies one managerial decision problem of the auction sites： how to combine penalties with commissions？ It is shown that when there exists secondary auction market, the auction whose penalty is a linear function of the seller＇s commission will be more efficient than the auction with only commissions but no penalties. It has also been proven that using this strategy can maximize the expected revenue for the seller, the auction site and their total expected revenues.
文摘Purpose： To evaluate the role of immediate and definitive management of Gustilo type Ⅲ A/B tibia fractures with intramedullary nailing and fasciocutaneous flap. Methods： From August 2010 to July 2012, 22 patients with Gustilo Grade Ⅲ A/B tibia fractures were managed with a single stage treatment of ipsilateral fasciocutaneous flap ＆ reamed intramedullary nailing and were included in the study. The severity of the injury was calculated with Ganga Hospital injury severity score. Results： The mean age of patients was 41 years and the follow-up time ranged from six months to one year. Among the 22 patients, 73% were type Ⅲ B fractures with upper leg involved in 55% of them. The time interval from injury to completion of surgery was 8 14 h. The incidence of bone infection requiring secondary procedure was 9%; the major and minor soft tissue complication rate was 9% and 14% respectively. The limb salvage rate was 100%. Conclusion： Multidisciplinary management of severe lower limb trauma is important and provides good outcomes, lntramedullary nailing and immediate flap fixation can achieve early bone union and good soft tissue coverage, leading to good outcomes in patient with Grade Ⅲ A ＆ B tibia fractures.
基金supported by the National Natural Science Foundation of China under Grant Nos.61273206 and 71471069
文摘In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects are sold sequentially and each buyer's valuation for the second object is k times that for the first one,and the true value of k is sellers' private information.The authors identify three factors which affect sellers' revelation strategies: The market's competition intensity which is characterized by the number of buyers,buyers' prior information about the second object,and the difference degree between two objects which is characterized by k.The authors give not only conditions under which revealing information about the second object in advance benefits the seller,but also the optimal releasing amount of information in the market with two sellers and one seller,respectively.
