相敏光放大器对光纤偏振模色散进行补偿的探讨

根据耦合非线性薛定谔方程,在考虑偏振模色散的情况下,采用数值方法仿真了含有相敏光放大器的高速光纤传输系统性能,获得了一组优化参量.仿真结果表明,相敏光放大器对于光纤偏振模色散的影响有一定的补偿作用.     

The efficient proportional Myerson values

In this paper we introduce a class of efficient extensions of the Myerson value for games with communication graph structures in which the surplus is allocated in proportion to measures defined on the graph. We show that the efficient proportional Myerson values can be characterized by efficiency, coherence with the Myerson value for connected graphs, and $\alpha$-fairness of surplus. The axiomatization implies a new characterization of the efficient egalitarian Myerson value proposed by van den Brink et al. (2012).     

通过消息监控识别罪犯的Markov模型

通过消息监控识别罪犯是一个十分有意义的实际问题。本文采用Markov模型的方法,将整个消息传递网络看作一个犯罪传递的Markov链.根据所收集到的消息估计出两个节点（人）之间犯罪传递的概率,得到一个Markov概率转移矩阵,并求出网络长期运行下去的稳定解,作为各节点（人）参与犯罪程度的度量。文章通过实例说明该方法的有效性。     

Communicative Suitability of Voice Following Radiotherapy for T1 Glottic Carcinoma: Testing the Reliability of a Rating Instrument

The objective of the study was to determine whether a communicative suitability rating instrument could be used in a meaningful way to assess functionality of voice following radiotherapy for T1 glottic cancer. Seventeen naive listeners judged the suitability of voice of a patient group with T1 glottic carcinoma (n = 20) just before treatment, a group of patients (n = 40) after radiotherapy, and a matched control group (n = 20) of normal speakers. Listeners rated suitability on a 10-point scale for 10 speaking situations, which supposedly make different demands. In order to validate scores on communicative suitability, ratings were related to perceptual voice quality evaluations and videolaryngostroboscopic evaluations. Results indicate that the concept of measuring listener judgments of communicative suitability of voice is basically sound. Raters are reliable and can discriminate between groups of normal and pathological voices. Patients with T1 glottic carcinoma (assessed before the start of treatment) have on average the least suitable voices. Following radiotherapy suitability is, on average, improved, but does not approach the suitability of normal voices. Ratings on communicative suitability were clearly related to perceptual voice quality aspects and videolaryngostroboscopic evaluations. A subset of three communicative suitability rating scales is recommended as part of the protocol for evaluating voice outcome after radiotherapy for early glottic cancer, besides perceptual evaluation of voice quality by trained and naive raters, videolaryngostroboscopy, acoustical analyses, and self-ratings of vocal performance.     

On the security of a class of discrete-time chaotic cryptosystems

In this Letter we analyze the security of some recently proposed chaotic cryptosystems and give methods to break the cipher to reveal the encrypted information. The method exploits the dependencies between the parameters and the output sequence of a dynamical system to reveal the secretly shared system parameters. For each encryption scheme a known plaintext attack and a ciphertext only attack are given.     

All-optical parallel data and address recovery scheme

In this paper, we have presented a parallel system model to recover data and address based on terahertz optical asymmetric demultiplexer (TOAD)/semiconductor optical amplifier (SOA)-assisted Sagnac gate. The architecture is based on a system which has its input information containing data and address. Here, we first convert the original data into a coded form with the help of input address. Then the coded information is transmitted through the optical routing channel. At the receiver end, the model simultaneously extracts data and address at any point of the routing channel. The operations of the circuits are studied theoretically and analyzed through numerical simulations. The variation of contrast ratio, amplitude modulation, extinction ratio and bit error rate with control pulse energy and switching crosstalk with gain ratio has been thoroughly investigated.     

On Strategic Defense in Stochastic Networks

This paper deals with the detection and prediction of losses due to cyber attacks waged on vital networks. The accumulation of losses to a network during a series of attacks is modeled by a 2-dimensional monotone random walk process as observed by an independent delayed renewal process. The first component of the process is associated with the number of nodes (such as routers or operational sites) incapacitated by successive attacks. Each node has a weight associated with its incapacitation (such as loss of operational capacity or financial cost associated with repair), and the second component models the cumulative weight associated with the nodes lost. Each component has a fixed threshold, and crossing of a threshold by either component represents the network entering a critical condition. Results are given as joint functionals of the predicted time of the first observed threshold crossing along with the values of each component upon this time.     

A novel temporal dark-bright solitons conversion system via an add/drop filter for signal security use

We propose a new design of a security scheme by using the nonlinear behaviors of temporal dark and bright solitons within a micro-ring resonator system for signal security application. When a dark soliton pulse is input into the proposed system, the chaotic signal is generated, where the required bright soliton pulse can be retrieved and detected by the add/drop filtering device. The chaotic wave form can be cancelled by using an add/drop device, which can be connected and used in the communication link. By using the appropriate ring parameters, simulation results obtained have shown that the soliton conversion can be performed. The ring radii used are within the ranges from 5 to 10 μms and A_eff=0.10-0.50 μm². In application, the chaotic signal is generated and formed by the dark soliton within a nonlinear micro-ring device. This can be seen by using the add/drop device, where the bright soliton is formed and detected, which is available to use in communication link. The different temporal soliton response time is seen, the response times of 169 and 84 ns are noted for temporal dark and bright solitons, respectively, which can also be used to form the security key.     

Communication: the essential factor when implementing management systems

Internal communication within a company is essential for the implementation and proper functioning of any ISO-based quality system. Moreover, staff empowerment and distribution of responsibilities are key points in the ISO 9000:2000 quality guides. Although not specifically mentioned in the quality guides, external communication plays a fundamental role in assuring customer satisfaction and obtaining good ideas to improve company performance. This paper has two main parts. First, the importance of internal and external communication is reviewed and it is shown that managers should allocate more resources to both areas. It is also demonstrated that environmental management systems are directly derived from the quality guides. Second, the results of an enquiry to assess the efforts being made by a group of Italian senior managers to improve internal and external communication are evaluated. Received: 8 March 2002 Accepted: 12 September 2002