船舶遇险报警通信设备使用策略

介绍了新航天测量船在航天工程中的重要作用,简述了各种船载通信设备的配备和功能。针对船载通信设备的特点,具体阐述了船载遇险报警通信设备的作用。特别是总结了在船舶遇险时,根据通信设备无线电波的覆盖范围和船舶所在的海区,对遇险报警设备进行正确使用的策略,以保障遇险报警及时而有效。最后举例说明了船舶在三大洋航行时,某点位发生遇险时,船舶如何求救的措施。     

看涨期权契约与看跌期权契约对比分析研究

在面临相同随机市场需求的情况下,本文对期权契约中的看涨期权与看跌期权契约进行了对比分析,以期为决策者在实际采购活动中选择不同类型的期权契约时提供决策依据。通过模型建立与求解分析,本文得出了销售商接受期权契约时,契约参数需要满足的条件及相应的订购策略;并进一步得出了两种期权契约下,供应链达到协调状态时的具体条件,分析了此时契约参数对供销双方利润的影响,继而给出了两种期权契约的适用范围以及供销双方的契约选择偏好。在此基础上,本文还给出了不同期权契约下,供销双方各自利润均不低于其自身保留利润时契约参数的取值范围,并证明了两种期权契约均可有效提高销售商的利润水平。最后,本文通过算例对上述结论进行了验证。     

Distributed Contention-Aware Call Admission Control for IEEE 802.11 Multi-Radio Multi-Rate Multi-Channel Wireless Mesh Networks

In this paper, we focus on call admission control (CAC) in IEEE 802.11 multi-radio multi-rate multi-channel (MR²-MC) wireless mesh networks (WMNs). CAC is the key component of QoS routing protocols. The goal of CAC is to protect existing flows from QoS violations and fully utilize available radio resource on channels. We propose a CAC mechanism, called Contention-Aware Multi-channel Call Admission Control (CMC), for MR²-MC WMNs based on IEEE 802.11 DCF. CMC is fully distributed, relies on local information to estimate the residual bandwidth of a path, and can be integrated into existing routing protocols for MR²-MC WMNs to provide QoS. We evaluate the performance of CMC via ns-2 simulations. The results show that CMC can precisely predict the end-to-end residual bandwidths of paths, successfully protects existing flows from QoS violations, and fully utilizes the bandwidths on channels.     

跳跃-扩散模型资产定价公式的数值计算方法

假定资产价格变化过程服从跳跃-扩散过程,那么基于它的欧式期权就满足一个偏积分-微分方程（PIDE）,本文利用差分法来离散这个PIDE方程,用两种迭代方法得到方程的数值解：基于雅可比正则分裂法和预条件共轭梯度法.     

物理量单位的智能导出算法及其应用

推导物理量的单位是物理作业中不可缺少的重要环节。提出一种物理量单位的智能导出算法,即计算机根据物理量的运算式自动推导出待求物理量的单位。实验结果表明,物理量单位导出及换算算法的结果正确,对算术运算式中的物理量单位导出及换算的正确率为100%,且物理量数值的运算正确。     

Game Options Analysis of the Information Role of Call Policies in Convertible Bonds

Abstract

In debt financing, existence of information asymmetry on the firm quality between the firm management and bond investors may lead to significant adverse selection costs. We develop the two-stage sequential dynamic two-person game option models to analyse the market signalling role of the callable feature in convertible bonds. We show that firms with positive private information on earning potential may signal their type to investors via the callable feature in a convertible bond. We present the variational inequalities formulation with respect to various equilibrium strategies in the two-person game option models via characterization of the optimal stopping rules adopted by the bond issuer and bondholders. The bondholders’ belief system on the firm quality may be revealed with the passage of time when the issuer follows his optimal strategy of declaring call or bankruptcy. Under separating equilibrium, the quality status of the firm is revealed so the information asymmetry game becomes a new game under complete information. To analyse pooling equilibrium, the corresponding incentive compatibility constraint is derived. We manage to deduce the sufficient conditions for the existence of signalling equilibrium of our game option model under information asymmetry. We analyse how the callable feature may lower the adverse selection costs in convertible bond financing. We show how a low-quality firm may benefit from information asymmetry and vice versa, underpricing of the value of debt issued by a high-quality firm.     

基于GPRS的IP电话技术研究

文章研究了一种的新的无线IP电话技术GPRS-VoIP,是一种基于GPRS接入的IP电话技术,可以实现和传统的基于电路交换的语音通话进行无缝切换.文中分析了该技术下的通话和传统GSM语音通话的无缝切换.文中还详细的分析了时廷、丢包、通话不连续等因素对基于GPRS接入的IP通话的影响和其对于带宽的需求,并提出了相应的解决方法.     

QoS provisioning for multiple non‐real‐time services in cellular wireless networks

Future mobile services are expected to include various non‐voice oriented services. One important category of non‐voice oriented mobile services is non‐real‐time services. When a mobile user establishes a connection to access non‐real‐time service, the mobile user usually cares about whether the total time to complete its data transfer is within its time tolerance. In addition, different mobile users may have different bandwidth requirements and different tolerances in the total completion time. It is essential for wireless systems to provide various mobile users with different total completion times. In this paper, two quality‐of‐service (QoS) metrics, called stretch ratio and eligibility percentage, are employed at a connection level to present the degree of the length of the total completion time. We devise a measurement based call admission control scheme that provides multiple QoSs for various mobile users which have different requirements of stretch ratios, eligibility percentages, and bandwidths. Extensive simulation results show that the measurement based call admission control scheme not only provides various satisfactory QoSs for mobile users but also produces high throughput. Copyright © 2010 John Wiley & Sons, Ltd.     

基于新型脑皮层的VoLTE视频感知指标监控方法

针对VoLTE视频通话中存在延迟、卡顿等问题,本文提出一种新型闹脑层算法的VoLTE视频通话质量的评估方法。首先,运用脑皮层算法的HTM算法对VoLTE时间序的指标进行检测,然后利用同比环比加权及HTM循环预测加权进行VoLTE感知指标异常值替换,构造能够实时发现指标异常状况的指标监控模型。其次使用时间序列连续性检测及补全功能、同比环比加权平均值再加权的方法提高异常数据训练的准确性。然后通过对比验证VoLTE失败码的预测结果,验证该模型的监控结果的有效性。     

蓝牙耳机的主观评测方法

蓝牙无线耳机的使用主要分为音乐和通话两种场景。本文提出了一种主观评测音乐播放效果的方法,结果表明耳机的音乐播放效果都是很不错的。在通话测试部分,按照3GPP和沃达丰的测试规范进行上下行响度的测试,并对噪声消除进行了主观评测,结果表明,语音通话部分还有很大的改进空间。