考虑渠道势力与服务负溢出效应的双渠道供应链决策研究

针对双渠道供应链中渠道势力的变化,构建制造商领导的Stackelberg模型(MS模型)、纵向Nash模型(VN模型)和零售商领导的Stackelberg模型(RS模型),并引入服务负溢出效应,考察供应链最优决策和绩效的差异。研究发现:(1)随着服务负溢出效应的增强,MS模型下的最优服务水平降低、批发价格上升,VN和RS模型下的最优服务水平不变、批发价格下降;(2)MS模型下,服务负溢出对零售价格的影响与溢出系数有关,VN和RS模型下的服务负溢出使零售价格下降;(3)制造商在MS模型中的利润最高,零售商在不同势力结构下的利润大小取决于服务负溢出系数;(4)在不同渠道势力下,供应链总绩效、直销渠道绩效和传统渠道绩效的变化,主要取决于服务负溢出系数和直销渠道潜在市场份额。

多尺度农业生态系统服务研究进展

农业生态系统服务是由受人类活动深度调控和影响的农业系统产生,其在提供有益生态系统服务的同时,也产生了诸多对人类福祉有负面影响的生态系统负服务。农业生态系统服务和负服务研究不仅关注传统的粮食安全,同时关注与生态安全的共赢,可为实现农业可持续发展提供新的科学视角。基于文献阅读,在明晰农业生态系统服务和负服务内涵及主要特征的基础上,旨在(1)归纳农业生态系统服务和负服务研究的核心尺度和热点议题;(2)梳理多级尺度的典型指标及适用性评估方法;(3)提出未来农业生态系统服务和负服务领域的关键发展方向。农业生态系统服务研究主要涉及田块、景观和区域三个核心尺度,随着尺度扩大,热点议题从关注田块农作物自身,到关注景观异质性及其关联,再到关注区域上与社会系统的结合。农业生态系统除了提供典型或特殊的粮食供给、授粉、杂草防控等服务,同时也带来农业废料、病虫害、生境破损等负服务。对于农业生态系统服务评估,定性和半定量方法通常可适用于多级尺度,而不同定量方法和模型的最佳适用尺度存在差异。未来可重点从时空权衡作用分析、供需和流动机制探索、生态价值实现及生态补偿制定方向为多尺度的农业景观规划与设计提供理论和实践支撑,从生态系统服务视角有效促进农业的可持续发展。

数字技术赋能生态农产品价值实现的路径研究

本文通过探讨生态农产品价值实现的内涵,提出实现生态农产品价值的关键在于促进价值的市场货币化和降低负服务,进一步阐述了数字技术赋能生态农产品价值实现的机理:数字技术赋能生态农业全产业链,促进生态农产品价值市场化;建设数字化绿色产业链,系统降低负服务。最后再提出数字技术赋能生态农产品价值实现的主要路径。

Resource Allocation with Dynamic Substrate Network in Data Centre Networks

The resource allocation problem in data centre networks refers to a map of the workloads provided by the cloud users/tenants to the Substrate Network(SN)which are provided by the cloud providers.Existing studies consider the dynamic arrival and departure of the workloads,while the dynamics of the substrate are ignored.In this paper,we first propose the resource allocation with the dynamic SN,and denote it as GraphMap-DS.Then,we propose an efficient mapping algorithm for GraphMap-DS.The performance of the proposed algorithm is evaluated by performing simulation experiments.Our results show that the proposed algorithm can effectively solve the GraphMap-DS.

The application of load balancing technology in campus network based on LVS-NAT

The concurrent processing and load capacity of a single server cannot meet the growing demand of users for a variety of services in a campus network system. This document put forward to solve this problem using load balancing techniques based on LVS-NAT, discussed the key technologies of LVS-NAT, designed and implemented campus network service system with LVS-NAT load balancing technology and tested. The results showed that this system improved the processing and load capacity of the concurrent server effectively and provided a good reference to building the efficient and stable digital campus network system.

Reliability analysis of web server cluster systems based on proportional hazards model

An approach for web server cluster(WSC)reliability and degradation process analysis is proposed.The reliability process is modeled as a non-homogeneous Markov process(NHMH)composed of several non-homogeneous Poisson processes(NHPPs).The arrival rate of each NHPP corresponds to the system software failure rate which is expressed using Cox s proportional hazards model(PHM)in terms of the cumulative and instantaneous load of the software.The cumulative load refers to software cumulative execution time,and the instantaneous load denotes the rate that the users requests arrive at a server.The result of reliability analysis is a time-varying reliability and degradation process over the WSC lifetime.Finally,the evaluation experiment shows the effectiveness of the proposed approach.

Network address translation traversal based on Bernoulli laws of large number in P2P streaming system

P2P streaming application must realize network address translation （NAT） traversal. To handle low success ratio of the existing NAT traversal algorithm, UPnP-STUN （UPUN） and port-mapping sample estimation （PMSE） algorithm are recommended in this paper. UPUN is the combination of UPnP and STUN, and PMSE utilizes port mapping samples added by symmetric NAT for different sessions to estimate regularity of port mapping of symmetric NAT, which takes advantage of the Bernoulli law of large numbers. Besides, for the situation that both peers are behind NAT, and to handle heavy relay server load when many inner peers want to communicate with each other, a peer auxiliary-relay （PAR） algorithm is presented. PAR lets outer peers with sufficient bandwidth act as relay servers to alleviate pressure of real server, which could avoid NAT traversal failure caused by single point failure of relay server. Finally, experiments show that the proposed algorithms could improve the success ratio significantly for NAT traversal in P2P streaming application as well as improve P2P streaming application applicability.

Real-time Business Network Selection Based on Auction Mechanism

In the framework of heterogeneous wireless networks,it is difficult for every user to obtain QoS-based services anywhere at any time.Due to heterogeneous networks,the dynamic network selection scheme needs to achieve seamless mobility,and also supports the optimization of service quality and load balancing.According to different business characteristics,this paper describes different real-time businesses in utility functions,and solves network selection problems for real-time businesses.Based on auction mechanism,it introduces the upset price in order to maximize online profits.Meanwhile,the network selection scheme is also helpful to control network congestion.The study of real-time business network selection based on auction mechanism can not only meet the demands of service quality of multiple realtime applications,but also achieves load balancing between different networks.

基于能值分析的农田生态系统服务评估——以河北省栾城县为例

农田从供给、调节和支持三个方面为人类提供生态系统服务的同时也消耗着其他系统和人类经济社会对其投入的资源,并且农田还提供了很多无益甚至有害的负服务。本文构建了基于能值分析框架的农田生态系统服务评估体系,以河北省栾城县为代表的农田生态系统为研究对象,从其消耗的资源、生态系统正服务、负服务产出3个方面分析农田生态系统的投入和产出情况;并构建基于生态服务的综合评价指标来探究农田生态系统的可持续发展情况。结果表明:农田消耗了大量的资源(2.75×1020sej),其中人类的不可更新工业辅助能最大(2.52×1020sej);农田提供的正服务(6.40×1020sej)主要是供给服务(3.70×1020sej),负服务供给中(2.02×1020sej),调节负服务比重最大(1.83×1020sej);能值可持续发展指数远小于1,且逐渐降低,综合评价农田属于严重的消费型系统。

A LIMITED RESOURCE VECTOR LOAD-BALANCING ALGORITHM FOR SOFTSWITCH-BASED HETEROGENEOUS CLUSTERED MEDIA SERVER

Based on the system feature of softswitch-based heterogeneous clustered media server, this paper proposed a limited resource vector load-balancing algorithm. The purpose of the algorithm was to balance the load of clusters by utilizing all system resources effectively and to avoid violent shaking of the system per- formance. A lot of simulations on the Petri net model of load balance system are conducted and the algorithm is compared with some traditional algorithms on balancing ability for heterogeneity, system throughput, re- quest response time and performance stability. The results of simulations show that the algorithm achieves system higher performance and it has excellent ability to deal with the heterogeneity of clustered media server.

Non-cooperative game for network access selection in heterogeneous integrated networks

The integration of different heterogeneous access networks is one of the remarkable characteristics of the next generation network,in which users with multi-network interface terminals can independently select access network to obtain the most desired service.A kind of unified quantification model of non-monotone quality of service(QoS) and a model of non-cooperative game between users and networks are proposed for heterogeneous network access selection.An optimal network pricing mechanism could be formulated by using a novel strategy which is used in this non-cooperative game model to balance the interests of both the users and the networks.This access network selection mechanism could select the most suitable network for users,and it also could provide the basis when formulating QoS standards in heterogeneous integrated networks.The simulation results show that this network selection decision-making algorithm can meet the users' demand for different levels service in different scenes and it can also avoid network congestion caused by unbalanced load.

Scalable Load-Adaptive Web-Based Network Management System： An Architectural Prototype

With the advances in enterprise communication and web technologies, web has evolved into a platform for delivering interactive applications. Web-based applications are revolutionizing both the features that can be delivered and the technologies for developing and deploying applications. In this paper, we present a web-based load-adaptive network management system framework. Our system is scalable, extendable, modular and based on open architecture. It is also load-adaptive as it can adapt to the increase in the number of incoming Web Service requests so that the systems performance will not degrade under heavy request loads. To evaluate the proposed architecture, we built a multi-tiered web application testbed with open-source components widely used in industry. Experimental studies conducted on the testbed demonstrated the effectiveness of the proposed approach. By developing the platform and making it available to the research community, we hope to catalyze the development of an open source stack for Web-based network management and monitoring.

An Information Systems Project Management Course Using a Service-Learning Model

This paper describes the implementation of an Information Systems （IS） capstone project management course that is a requirement for graduating seniors in an undergraduate Computer Information Systems （CIS） program at a regional university. The description provides a model which includes the culmination of students＇ academic training in an IS curriculum which is part of a Bachelor of Business Administration （BBA） program in an accredited college of business. The course requires an application of technical and business skills, as well as systems development and project management skills--while students are working on an actual IS project for an external sponsoring organization. Rationale for implementing this type of course includes the benefits it provides to the students, the project sponsors, and the IS department providing the course. Feedback from the course is used as integral part of the C1S curriculum assessment process used for accreditation purposes.

气候变化对农业生态系统服务的影响及适应对策

由于农业生态系统的脆弱性,气候变化给农业生态系统服务持续供给带来巨大挑战。以往研究分析了农业生态系统受气候变化的影响及响应,但尚缺乏气候变化对农业生态系统服务的影响及适应对策的综合分析。本研究从农业景观多样性的角度出发,综述了气候变化对农作物产出、调节服务稳定性及文化服务供给的影响机制及当前采取的主要适应措施,并从深化气候变化对多重农业生态系统服务综合影响研究、探索农业生态系统服务对气候变化的适应机制、加强模型模拟研究以及加强适应措施与政府决策的联系等方面进行了展望,以期为国家应对气候变化政策制定与行动实施提供科学依据。

农业生态产品及其价值实现路径

农业生态产品价值实现对我国粮食安全、生态保护、重要战略布局意义重大。本研究梳理了农业生产系统和农业生态产品(农产品、其他生态系统服务与负服务)的概念与边界,基于能值分析构建了农业生产系统所提供的服务核算方法体系,核算了我国单位面积典型农产品生态系统服务与负服务,并进一步提出分类化的农业生态产品价值实现路径:1)已经通过市场化价值实现的农业生态产品需要通过提升绿色度、特殊度和建立农业产业链等实现溢价增值;2)尚未通过市场化价值实现的农业生态产品需要进行价值补偿途径,或通过生态产品赋能及区域共用品牌质量承诺实现价值变现;3)通过多途径减少温室气体排放、通过土地养分管理策略减少氮磷、农药、杀虫剂对生态系统和人群健康的损害,以及通过合理的景观结构减少农业生态系统负服务的产生,以此实现农业生态产品的价值保值;4)还可通过取消二次农业补贴、建立生态交易平台和生态产品认证等推动相关的金融方案。本研究有助于提出农业生态产品价值实现路径,促进绿色金融发展,推动自然资源管理能力现代化。

Medical service utilisation, economic burden and health status of patients with rare diseases in China

Many patients with rare diseases not only suffer from more severe conditions but often receive less disease management, which is one significant public health concern globally. Few practice-based surveys focus on the care of patients with rare diseases. In the present study, we aimed to investigate medical service utilization, economic burden and health status of patients with rare diseases in China. A cross-sectional questionnaire survey focusing on patients with rare diseases was conducted. Descriptive analysis was conducted to examine the sociodemographic characteristics, medical service utilization, economic burden and health status. Logistic regression analysis was applied to explore influencing factors of self-rated health. A total of 982 patients with 81 types of diseases were included in this survey. We found that 58.2% of patients experienced misdiagnosis, and 35.2% of the patients were misdiagnosed for at least five times. Moreover, 65.8% of patients traveled to hospitals to seek medical services, and 92.1% of patients paid expenses for their treatment. However, only 1.3% of patients could afford their medical expenditure without debts, and 86.8% of patients regarded their health status as bad or moderate. Significant factors correlated with health status were economic status, gender, age, employment and household size. From this study, the accessibility of medical service utilization, the affordability of medical economic burden, and the condition of health status for patients with rare disease in China were considerably poor. Basic medical insurance did not play its role in improving the utilization of medical services and the affordability of medical costs. Social support should be encouraged to improve patients＇ health status.

Strong stability of Nash equilibria in load balancing games

We study strong stability of Nash equilibria in load balancing games of m(m 2)identical servers,in which every job chooses one of the m servers and each job wishes to minimize its cost,given by the workload of the server it chooses.A Nash equilibrium(NE)is a strategy profile that is resilient to unilateral deviations.Finding an NE in such a game is simple.However,an NE assignment is not stable against coordinated deviations of several jobs,while a strong Nash equilibrium(SNE)is.We study how well an NE approximates an SNE.Given any job assignment in a load balancing game,the improvement ratio(IR)of a deviation of a job is defined as the ratio between the pre-and post-deviation costs.An NE is said to be aρ-approximate SNE(ρ1)if there is no coalition of jobs such that each job of the coalition will have an IR more thanρfrom coordinated deviations of the coalition.While it is already known that NEs are the same as SNEs in the 2-server load balancing game,we prove that,in the m-server load balancing game for any given m 3,any NE is a(5/4)-approximate SNE,which together with the lower bound already established in the literature yields a tight approximation bound.This closes the final gap in the literature on the study of approximation of general NEs to SNEs in load balancing games.To establish our upper bound,we make a novel use of a graph-theoretic tool.

Batch RSA Signature Scheme

We describe a batch RSA digital signature scheme in which a signer can sign messages for multiple recipients simultaneously. The construction is quite efficient due to the batch signing method. This is useful to improve the performance of a high-loaded signing server, for example a secure electronic transaction （SET） gateway. Theoretical calculations and experimental results show that the proposed scheme can improve the performance of the signing server significantly.