Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 17 - 32 of 40

  • Two-period supply chain with flexible trade credit contract

    Yang, Honglin   Zhuo, Wenyan   Zha, Yong   Wan, Hong  

    This paper studies a two-period supply chain that consists of a retailer and a supplier. A newsvendorlike retailer is capital constrained and orders products using a supplier's trade credits to satisfy uncertain market demand. Most existing studies show that the retailer always postpones payment until the due date. To recall the loans earlier, we present a case in which the supplier, as a Stackelberg leader, offers an incentive of a discounted wholesale price in the second order to entice the retailer to choose flexible early payment. The proposed incentive is related to the retailer's early payment time in the first period. In the presence of bankruptcy risks for both the retailer and supplier, we propose a continuous newsvendor model of a two-period supply chain to analyze the decisions involved in the flexible trade credit contract. The analytic forms confirm that such an incentive can improve the decentralized supply chain efficiency and decreases the supplier's trade credit risk. The retailer always prefers early payment to payment around the due date to increase revenues. Furthermore, the action of paying early might help the retailer adjust cash flow between the two periods. We also find that a revenue sharing contract significantly affects the retailer's payment behavior and supplier's wholesale price. The numerical simulations support our results. (C) 2016 Elsevier Ltd. All rights reserved.
    Download Collect
  • Effect of terrestrial vegetation growth on climate change in China

    Li, Long   Zha, Yong   Zhang, Jiahua   Li, Yunmei   Lyu, Heng  

    Download Collect
  • Dynamic pricing in the presence of reference price effect and consumer strategic behaviour

    Chen, Kehong   Zha, Yong   Alwan, Layth C.   Zhang, Lu  

    Download Collect
  • Two-stage cooperation model with input freely distributed among the stages

    Zha, Yong   Liang, Liang  

    Shared flow has been widely used in production scenarios where inputs and outputs are shared among various activities. In DEA literature, shared flow represents situations that DMUs are divided into different components that require common resources or produce goods or services obtained through collaboration among them. The objective of this paper is to offer an approach for studying shared flow in a two-stage production process in series, where shared inputs can be freely allocated among different stages. A product-form cooperative efficiency model is proposed to illustrate the overall efficiency of the DMU, and the relationship between the stages. First, we use a game-theory framework to decide the upper and lower bounds of the efficiencies of the stages in a non-cooperative context. A heuristic is suggested to transform the non-linear model into a parametric linear one, which is then used to solve the cooperative model. The model is justified by a numerical evaluation of bank performances. (C) 2010 Elsevier B.V. All rights reserved.
    Download Collect
  • Remote estimation of chlorophyll a in optically complex waters based on optical classification

    Le, Chengfeng   Li, Yunmei   Zha, Yong   Sun, Deyong   Huang, Changchun   Zhang, Hong  

    Accurate assessment of phytoplankton chlorophyll a (Chla) concentration in turbid waters by means of remote sensing is challenging due to optically complexity and significant variability of case 2 waters, especially in inland waters with multiple optical types. In this study, a water optical classification algorithm is developed, and two semi-analytical algorithms (three- and four-band algorithm) for estimating Chla are calibrated and validated using four independent datasets collected from Taihu Lake, Chaohu Lake, and Three Gorges Reservoir. The optical classification algorithm is developed using the dataset collected in Taihu Lake from 2006 to 2009. This dataset is also used to calibrate the three- and four-band Chla estimation algorithms. The optical classification technique uses remote sensing reflectance at three bands: Rrs(G), Rrs(650), and Rrs (NIR), where G indicates the location of reflectance peak in the green region (around 560 nm), and NIR is the location of reflectance peak in the near-infrared region (around 700 nm). Optimal reference wavelengths of the three- and four-band algorithm are located through model tuning and accuracy optimization. The three- and four-band algorithm accuracy is further evaluated using other three independent datasets. The improvement of optical classification in Chla estimation is revealed by comparing the performance of the two algorithms for non-classified and classified waters. Using the slopes of the three reflectance bands, the 138 reflectance spectra samples in the calibration dataset are classified into three classes, each with a specific spectral shape character. The three- and four-band algorithm performs well for both non-classified and classified waters in estimating Chla. For non-classified waters, strong relationships are yielded between measured and predicted Chla, but the performance of the two algorithms is not satisfactory in low Chla conditions, especially for samples with Chla below 30 mg m(-3). For classified waters, the class-specific algorithms perform better than for non-classified waters. Class-specific algorithms reduce considerable mean relative error from algorithms for non-classified waters in Chla predicting. Optical classification makes that there is no need to adjust the optimal position to estimate Chla for other waters using the class-specific algorithms. The findings in this study demonstrate that optical classification can greatly improve the accuracy of Chla estimation in optically complex waters. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.
    Download Collect
  • Relationship between polymorphism of angiotensin-converting enzyme gene insertion/deletion and risk of hepatocellular carcinoma in a Chinese Dai population.

    Zha, Yong   Gan, Ping   Liu, Qin   Tan, Jing  

    INTRODUCTION: The angiotensin-converting enzyme gene (ACE) is directly involved in the process of cancer cell proliferation, differentiation, apoptosis and angiogenesis. It also plays a vital role in inducing liver fibrosis and developing hepatocellular carcinoma (HCC). The aim of this study was to investigate the relationship between ACE insertion/deletion (I/D) polymorphism and the risk of HCC in a Chinese Dai population.; MATERIALS AND METHODS: We conducted a study including 210 patients with HCC and 206 healthy controls in Yunnan Cancer Hospital between January 2012-January 2014. I/D genotypes of ACE were determined with polymerase chain reaction (PCR) amplification of DNA from peripheral blood leukocytes.; RESULTS: The ACE D allele was more frequent in the HCC cases than in the controls (51.7% vs 44.4%, p=3D0.036). Individuals with DD genotypes were associated with increased HCC risk compared with those with the II genotypes (odds ratio (OR), 1.911; 95% confidence interval (CI), 1.081-3.379; p=3D0.025). However, the ACE I/D polymorphism were not significantly associated with any clinicopathological characteristics such as the tumor stage, serum alpha-fetoprotein (AFP) level, and hepatitis B virus (HBV) infection.; CONCLUSIONS: The DD genotypes of ACE I/D polymorphism might contribute to the prediction of HCC risk in a Chinese Dai population. =C2=A9 The Author(s) 2014.
    Download Collect
  • A TWO-STAGE DEA APPROACH WITH FEEDBACK FOR TEAM PERFORMANCE EVALUATION

    Zha, Yong   Ding, Xixiang   Liang, Liang   Huang, Zhimin  

    With rapid social development and deepening division of labor, more and more complex projects are required to be carried out in a team form. When evaluating team performance, previous research has usually treated team as a united entity. However, the operating environment of the team has a significant impact on its members and the interaction between them greatly influences the team's efficiency. To better evaluate team performance, we propose a circle loop to illustrate the relationship between the operating environment of the team and its members. A two stage DEA model with feedback is developed to evaluate the team performance, together with the efficiencies of the operating environment and team members as well as their impacts on overall efficiency. Various conditions of the team are discussed to illustrate that team performance depends on the assumption of the conditions.
    Download Collect
  • Influence of the 17 April 2006 Asian dust storm on Moderate Resolution Imaging Spectroradiometer data for land cover identification

    Zha, Yong   Li, Lin  

    China suffers from some of the most harmful dust storms. Dust storms occur every year in China and have significant effects on remote sensing of land surface. This study addresses the effect of dust storms on Moderate Resolution Imaging Spectroradiometer ( MODIS) imagery for land cover identification. Results from supervised classification of two MODIS data sets acquired before and during a dust storm of April 2006 are compared, and the mechanism responsible for such effects is analyzed. An index called influence intensity was proposed to quantify the effect of dust storms on different MODIS bands for land cover identification. Results from this study indicate that dust storms modified spectral characteristics of land cover types and resulted in decreased spectral contrast among land cover types. Out of 10 MODIS bands used in this study, dust storm yielded the most significant effect on MODIS bands 3, 18, and 19 for land cover identification. Conversely, MODIS bands 4, 5 and 6 were affected to a low degree.
    Download Collect
  • Dealing with missing data based on data envelopment analysis and halo effect

    Zha, Yong   Song, Ali   Xu, Chuanyong   Yang, Honglin  

    This research attempts to solve the problem of dealing with missing data via the interface of Data Envelopment Analysis (DEA) and human behavior. Missing data is under continuing discussion in various research fields, especially those highly dependent on data. In practice and research, some necessary data may not be obtained in many cases, for example, procedural factors, lack of needed responses, etc. Thus the question of how to deal with missing data is raised. In this paper, modified DEA models are developed to estimate the appropriate value of missing data in its interval, based on DEA and Inter-dimensional Similarity Halo Effect. The estimated value of missing data is determined by the General Impression of original DEA efficiency. To evaluate the effectiveness of this method, the impact factor is proposed. In addition, the advantages of the proposed approach are illustrated in comparison with previous methods. (C) 2012 Elsevier Inc. All rights reserved.
    Download Collect
  • Haze detection by using modified normalized difference haze index in Beijing,Tianjin,and Hebei province

    Han, Xinlei   Yao, Fengmei   Zhang, Jiahua   Waqar, Mirza Muhammad   Zha, Yong   He, Junliang  

    This paper presents the development of index to detect haze from moderate resolution imaging spectroradiometer remote sensing data. Detection of haze over a large area has always been a problem. This study focuses on Beijing, Tianjin, and Shijiazhuang cities in China. These cities have suffered the worst hazy weather in recent years. The spectral influence of haze on surface features was determined through analysis of the spectral variations of surface covers between hazy and haze-free days. A spectral index known as modified normalized difference haze index (m-NDHI) is developed that can be used to monitor haze distribution and intensity. Correlation analysis of the derived m-NDHI and previously developed NDHI with in situ PM2.5 (particulate matter with diameter <2.5 mu m) data reveals that m-NDHI over water bodies has a coefficient of 0.7096, 0.5864, and 0.4857 and NDHI has coefficient of 0.5625, 0.5321, and 0.4618 with PM2.5 for Beijing, Tianjin, and Shijiazhuang, respectively, in winter. Moreover, the correlation of m-NDHI with PM2.5 is 0.4097, 0.8092, and 0.5546 during the spring, summer, and autumn, respectively, in Beijing. This developed index can be a much easier and more effective method to detect haze in large scales from remotely sensing data and characterize the situation of urban atmospheric pollution. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
    Download Collect
  • Validation of a Quasi-Analytical Algorithm for Highly Turbid Eutrophic Water of Meiliang Bay in Taihu Lake, China

    Le, Cheng Feng   Li, Yun Mei   Zha, Yong   Sun, Deyong   Yin, Bin  

    In many hydrological studies and applications, it is desirable to know the absorption property of water bodies. In order to derive this inherent optical property of waters from remote sensing reflectance, a multiband quasi-analytical algorithm (QAA) was calibrated and validated for the highly turbid water of Taihu Lake in China. A data set collected on November 8, 2007, from Meiliang Bay of Lake Taihu was first used to calibrate a regional QAA algorithm for this area, and other two independent data sets, which were collected on August 22, 2006, and November 10, 2008, from the same area, were used to further validate the local algorithm. By shifting the reflectance wavelength from the red region to near infrared, the local QAA algorithm works well for this highly turbid water, the percent difference between the derived and measured absorption coefficients is less than 20% for all 13 samples in the data set of 2007, and most of them are less than 10%. The regional calibrated algorithm also has great result in deriving the absorption for the data set of 2008. However, the performance of the local algorithm also has various seasonal properties. It failed in deriving absorption for the data set of August 2006, unless the reference wavelength is shifted to even more long ones. It has been suggested in this paper that the seasonal and regional information is necessary for using the QAA algorithm in different optical property waters.
    Download Collect
  • Determination of cross-efficiency under the principle of rank priority in cross-evaluation

    Wu, Jie   Liang, Liang   Zha, Yong   Yang, Feng  

    As an extension to data envelopment analysis (DEA), cross-efficiency evaluation method not only provides a ranking among the decision making units (DMUs), but also eliminates unrealistic DEA weighting schemes without requiring a prior information on weight restrictions. A factor that possibly reduces the usefulness of the cross-efficiency evaluation method is that the cross-efficiency scores may not be unique due to the presence of alternate optima. As a result, it is recommended that secondary goals be introduced in cross-efficiency evaluation. In some cases, pursuing the best ranking is more important than maximizing the individual score. This paper seeks to propose a novel model for optimizing the ranking order for each DMU to determine the final cross-efficiency of all DMUs. Finally, preference voting application is presented to illustrate the differences between the proposed and existed models. (C) 2008 Elsevier Ltd. All rights reserved.
    Download Collect
  • A four-band semi-analytical model for estimating chlorophyll a in highly turbid lakes: The case of Taihu Lake, China

    Le, Chengfeng   Li, Yunmei   Zha, Yong   Sun, Deyong   Huang, Changchun   Lu, Heng  

    Accurate estimation of phytoplankton chlorophyll a (Chla) concentration from remotely sensed data is particularly challenging in turbid. productive waters. The objectives of this study are to validate the applicability of a semi-analytical three-band algorithm in estimating Chla concentration in the highly turbid, widely variable waters of Taihu Lake, China, and to improve the algorithm using a proposed four-band algorithm. The improved algorithm is expressed as [Rrs(lambda(1))(-1)-Rrs(lambda(2))(-1)][Rrs(lambda(4))(-1)-Rrs(lambda(3) )(-1)](-1). The two semi- analytical algorithms are calibrated and evaluated against two independent datasets collected from 2007 and 2005 in Taihu Lake. Strong linear relationships were established between measured Chla concentration and that derived from the three-band algorithm of [Rrs(-1)(660)-Rrs(-1)(692)]Rrs(740) and the four-band algorithm of [Rrs(-1)(662)-Rrs(-1)(693)][Rrs(-1)(740)-Rrs(-1)(705)](-1). The first algorithm accounts for 87% and 80% variation in Chla concentration in the 2007 and 2005 datasets, respectively. The second algorithm accounts for 97% of variability in Chla concentration for the 2007 dataset and 87% of variation in the 2005 dataset. The three-band algorithm has a mean relative error (MRE) of 43.9% and 34.7% for the 2007 and 2005 datasets. The corresponding figures for the four-band algorithm are 26.7% and 28.4%. This study demonstrates the potential of the four-band model in estimating Chla even in highly turbid case 2 waters. Crown Copyright (C) 2009 Published by Elsevier Inc. All rights reserved.
    Download Collect
  • Downregulation of Rap1 promotes 5-fluorouracil-induced apoptosis in hepatocellular carcinoma cell line HepG2.

    Zha, Yong   Gan, Ping   Yao, Qian   Ran, Feng-Ming   Tan, Jing  

    Recent studies have revealed that repressor/activator protein (Rap1) not only protects telomeres from sister chromatid exchange, but also functions in genomewide transcriptional regulation. Knockdown of Rap1 sensitizes breast cancer cells to adriamycin-induced apoptosis. However, little is known about the role of Rap1 in the progression of hepatocellular carcinoma (HCC). The present study aimed to investigate the functions of Rap1 in HCC progression and to determine whether targeting the Rap1 signaling pathway may be of therapeutic value against HCC. We found knockdown of Rap1 by microRNA (miRNA) interference enhanced significantly apoptosis and 5-fluorouracil (5-FU) chemosensitivity in HepG2 cell line. Rap1 miRNA downregulated nuclear factor-kappaB p65 (NF-kappaB p65) expression, and upregulated inhibitor of NF-kappaB (IkappaB) expression. In vivo, Rap1 miRNA combined with 5-FU treatment led to a significant reduction of tumor growth as compared with 5-FU alone. The results indicate that Rap1 miRNA can effectively enhance sensitivity of HepG2 cell line to 5-FU chemotherapy in vitro and in vivo.=20
    Download Collect
  • Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance

    Li, Na   Shi, Kun   Zhang, Yunlin   Gong, Zhijun   Peng, Kai   Zhang, Yibo   Zha, Yong  

    Download Collect
  • PERFORMANCE IMPROVEMENT ON CROSS-EFFICIENCIES AND APPLICATIONS TO COMPETITIVE ADVANTAGES OF CHINESE CITIES

    Zha, Yong   Liang, Liang   Wu, Jie   Huang, Zhimin  

    As a Data Envelopment Analysis (DEA) extension tool, cross-evaluation method was developed to evaluate Decision Making Units' (DMUs) performances in a competitive situation with limited demand. It identifies DMUs with best performances and rank them by applying peer evaluation mode instead of self-evaluation mode. However, it has limitations in efficiency improvement. That is, it fails to give direct information on how to improve efficiencies of the inefficient DMUs. In this chapter, we propose an alternative way to apply cross-evaluation in efficiency improvement. First, an appropriate and feasible suggestion is proposed to minimize the variation between the weights of a DMU's own optimal Charnes-Cooper-Rhodes (CCR) efficiency and the weights guaranteeing its cross-efficiency score. We exploit several transformations to convert nonlinear programming into a linear one. As a result, an overall optimal set of the weights is obtained, which precisely illustrate the preferences of decision makers and exact characteristics of production process of the evaluated DMU. A further discussion is advanced to examine the existence of non-uniqueness of the weights and to differentiate various sets of the optimal weights by suggesting a unique feasible set of multipliers to best represent the alternative weights selection criterion. Moreover, we develop several models to reallocate the inputs and outputs of inefficient DMUs with minimum amelioration as well as consideration of the preference of decision makers. Finally, we apply our models to evaluate competitive advantages of Chinese cities.
    Download Collect
1 2 3

Contact

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback