突发信道下无线ATM的前向差错控制方案

在无线ATM网络中，无线信道的高误码率和突发特性要求对无线ATM信元进行较强的误码保护。本文提出了一种有效的前向差错控制（FEC）方案，对信元头采用较强的FEC，对信息域采用较弱的FEC，并针对信道特性和采用的前向差错控制编码的特点进行元头信元内交织，文中对无线ATM信元在突发信道下的信元丢失率和信元信息错误率进行了分析，仿真结果表明该方案在降低信元信息错误率的同时有效地降低了信元丢失率。     

清除阻塞的M/P/C/C 排队系统仿真

对清除阻塞型M／P／C／C排队系统进行了大量的仿真研究，结果表明在平均到达率及平均服务时间分别对应相同的情况下，其呼叫损失概率与爱尔兰-B公式符合得很好。这一结论对通信网络规划过程中考虑业务流的自相似性有重要意义。     

基于SNSP的呼叫处理模型及其性能分析

本文研究了我们在“无线接入中心交换局系统”（ＷＡＣＯＳ）中提出的基于“简单网络信领协议”（ＳＮＳＰ）的“分布式呼叫处理模型结构”（ＤＣＰＡ）。该结构根据路由状态执行呼叫许可控制（ＲＣＡＣ），采用“预建立链路”和“并行连接控制”（ＰＣＣ）相结合的“改进的并行连接控制”（ＩＰＣＣ）算法加快呼叫处理进程。分析结果表明，同样的网络条件下〉ＲＣＡＣ更能保证业务尤其是低优先级业务的；ＱｏｓＤＣＰＡ结构更易实现     

用于多级交换网络的一种高效自寻路技术

自寻路交换是多级交换网络中的一种常用技术,但它容易因冲突而形成网络内部阻 塞 。为减少连续冲突,进一步提升网络性能,基于三级Clos网络,提出了一种新的高效 自寻路机制。通过在交换网络前端采取“信元间插”策略,将分组的连续信元在时间轴上 打散,保证业务被均匀地发送至网络中,从而大大减轻了网络内部阻塞;同时,通过在第一 级交换单元中设置“逻辑指示器”,为不同的业务流合理地选取第二级交换单元,一定程度 上保证了第二级的负载均衡。理论分析和仿真实验表明,与CRRD（Current Round-Robin Di spatching）等其他交换调度方 式相比,新自寻路机制下的信元平均网络时延明显减小。     

短波选频和选址呼叫技术的研究与实践

本文从短波模拟话音通信的实际情况出发,讨论了短波无中心组网中,实时选频和数字选址技术.提出了以绝对值信噪比(ASNR)代替常用信噪比进行信道评判的实时选频方案,和以双门限连续判决器及简易纠错码-(7,4)循环码的软件编译码,作为数字选址呼叫信可靠传输、识别手段的数字选址呼叫方案,并通过了实验验证.     

千亿暴富广告幕后调查

“10亿元资金倍增到1000亿元，否则倒赔1亿元。”作为投资人，看到这样的广告你会信吗？     

无线双通道网络话音业务信道接入性能分析

无线双通道网络能够有效解决战术环境下码分组网数目过小造成的码分资源浪费问题。混合业务传输环境下,实时话音业务信道接入性能是衡量无线双通道网络性能的关键指标之一。通过使用一种理想的固定时分信道带宽分配方案,在保障话音业务传输实时性的条件下,分别从单跳网络拓扑和多跳网络拓扑结构给出了双通道网络可用信道数目。使用基于优先权的混合业务多服务台离散时间排队模型分析了双通道网络的话音业务平均数目、呼叫阻塞概率、平均网络吞吐量和信道利用率等性能。数值计算结果证明:相比传统网络,双通道网络在混合业务高负载条件下能够容纳更多的话音业务并具有更低的呼叫阻塞概率。     

缔元信“TA心通”亮相领跑“大数据α”时代

8月29日下午．大数据α·缔元信新品发布会在北京神舟国际酒店隆重召开。中国互联网协会秘书长助理石砚升、缔元信CEO秦雯、总裁梅涛及业界同行、媒体精英纷纷相聚于此，见证了国内首例大数据应用产品“TA心通”首秀。     

异步传递模式的协议原理及其关键技术的研究进展

异步传递模式（ATM）一致被看成宽带数据骨干网的基础传输技术。本文首先简要介绍ATM协议的基本结构和ATM信元交换的基本原理，并说明ATM网络的资源管理方案，然后具体分析ATM信元交换及其与IP网结合所面临的一些关键技术问题，并讨论了解决这些问题所采用的方法及其研究进展，最后总结了今后有关ATM技术应用急需解决的一些问题。     

宅急送弄丢21万珠宝只赔几百

珠宝快递离奇"丢失"21万元只赔162元日前,在北京经营珠宝生意的王女士找宅急送运送价值21万元的珠宝首饰,货物寄到北京之后在收货人不知情的情况下,被宅急送的一位营业厅经理签收,当收货人去提货时却被告知货物"丢失"。     

LEO卫星通信系统的呼叫接入性能分析

在均匀业务模型的基础上，根据LEO卫星通信系统自身特点，提出了一种简单有效的呼叫接入控制策略，这种策略能在非均匀业务下较好地工作，此时系统新呼叫阻塞率和切换呼叫失败率能达到更好的平衡。在分析随机接入（RANDOM）算法和预留保护信道（GC）算法的基础上，进行了计算机仿真，并给出了相应的仿真结果。     

大规模通信网络带宽分配的快速分解优化

本文对大规模通信网络带宽分配的计算过程进行了研究，发现现有分解优化计算的方法中限制计算速度的瓶颈在于主节点上的等效流量的计算，在此基础上提出一种用近似公式代替递推公式计算呼叫损失概率的方法，将它运用于带宽分配算法中，计算速度大力提高，而计算相对误差为10％左右。     

Basket Composition and Choice Among Direct Channels: A Latent State Model of Shopping Costs

Shoppers of multi-channel retailers often place orders using different channels on different shopping occasions. The differential use of channels is related to both basket composition and channel characteristics, such as the ability of the channel to provide additional information that resolves uncertainty about the purchase. In this paper, we examine the impact of basket composition on the choice among direct channels. We develop a two-stage, shopping cost model with two, latent states. Given a shopping basket, the shopper first decides if she needs additional information about items in the basket. If she is uncertain about the items in the basket meeting her needs, she uses an information rich channel, such as the retailer's website or call center, and risk reduction costs become salient in addition to the other shopping costs. If she does not require additional information, she places her order by choosing among all available channels, and she may incur a welfare loss from making a purchase that does not optimally meet her needs. We operationalize welfare loss with Shannon information and various metrics based on purchase history.Our empirical setting is a data set from a catalog retailer that offers multiple direct channels. Our estimates show that basket composition impacts channel choice. Large baskets shift to the Internet channel, suggesting that the Internet channel has lower ordering costs. High-risk baskets shift to call centers and this suggests that the call center has lower risk reduction costs. Collectively these estimates provide evidence for the notion of channel specialization—some channels are better at addressing certain shopping costs compared to others. Our estimates also show that electronic self-service channels have high initial access costs and a significant learning curve compared to the call center suggesting that these channels might be better suited to heavy users. We use the estimated model to quantify the value of channels, to identify categories that need risk reduction, and to segment and target shoppers for Internet ordering based on basket size and the potential to accumulate experience.     

基于神经网络的宽带ATM网的自适应和最优化控制

<正> 克林顿总统的第二个任期已经开始。在经历了1995～1996年中美关系的曲折与反复之后,克林顿新政府的对华政策究竟会呈现什么样的走向,其对华政策是否会保持一定的连续性与稳定性,哪些因素将制约调整后的对华政策的贯彻,这些正是本文试图探讨的。     

Shortfall aversion

Shortfall aversion reflects the higher utility loss of spending cuts from a reference than the utility gain from similar spending increases. Inspired by Prospect Theory's loss aversion and the peak‐end rule, this paper posits a model of utility from spending scaled by past peak spending. In contrast to traditional models, which call for spending rates proportional to wealth, the optimal policy in this model implies a constant spending rate equal to the historical peak when wealth is relatively large. The spending rate increases when wealth reaches a model‐determined multiple of peak spending. In 1926–2015, shortfall‐averse spending is smooth and typically increasing.     

The internationalization process model: A proposed view of firms’ regular incremental and irregular non-incremental behaviour

Commitment in the internationalization process model (IP-model) is challenged by the search for knowledge through experience and interactions. Critics opposing this logic even forced the founder of the model to call for the need for integration of other elements in order to understand irregular behaviour like rapid internationalization, loss of commitment and market exit. Aligned with this call, the paper raises the question of how the IP-model can be applied to analyse both regular/incremental and irregular/non-incremental behaviour of the firms. To reach an answer, the paper proposes a theoretical view by adding expectation and unknown uncertainty to the IP-model and examines this in a case study. The contribution is a further development of the IP-model by merging these two concepts that provide tools for understanding irregular behaviour. The paper analyses a Swedish firm's internationalization in different foreign markets for the period of 1995–2009. Conclusions support the understanding of how the model can describe regular incremental and irregular non-incremental commitment behaviour.     

定金合同中的期权特性及价值分析

在定金合同中,定金作为履行合同的担保,可以起到合同成立的证明作用,同时还具有惩罚性.由于合同是到期才执行,这种实物期权属于一种欧式期权.合理的定金往往成为吸引客户的重要手段.定金太高会造成有价值客户的流失;定金太低又达不到锁定客户的目的一客户也许会放弃买权.科学合理地量化定金标准显得很重要.在商业交易中,定金合同成立的同时,即出现了买权价值和卖权价值.根据合同的期权特征,引入Black-Scholes定价模型对其价值进行估计,买权受双方利益的限制而发生变异,即其价值被限定在某个最高值之内;卖权却在这个利益的竞争过程中被虚化.     

Some antecedents of exclusivity in bilateral interorganizational relationships

In bilateral interorganizational relationships, individual firm's self-interest is subordinate to the larger interest of the collective system. Bilateral governance is facilitated by exclusivity under certain conditions. Exclusive relationships draw partners closer and improve coordination. However, exclusivity leads to a loss of flexibility in dealing with turbulent environments. We test relationships between exclusivity and antecedent variables from transaction-cost analysis, resource-dependence theory, and organization theory. We find that while relationship-specific investment calls for more exclusivity, interdependence and rapid technological change call for less. Further, in the computer and semiconductor industry, exclusivity is negatively related to perceived effectiveness. Hence exclusivity should be used judiciously in the management of bilateral interrorganizational relationships.