Specifying real-time properties with metric temporal logic

This paper is motivated by the need for a formal specification method for real-time systems. In these systemsquantitative temporal properties play a dominant role. We first characterize real-time systems by giving a classification of such quantitative temporal properties. Next, we extend the usual models for temporal logic by including a distance function to measure time and analyze what restrictions should be imposed on such a function. Then we introduce appropriate temporal operators to reason about such models by turning qualitative temporal operators into (quantitative) metric temporal operators and show how the usual quantitative temporal properties of real-time systems can be expressed in this metric temporal logic. After we illustrate the application of metric temporal logic to real-time systems by several examples, we end this paper with some conclusions.Part of this research has been performed at the Eindhoven University of Technology when the author was working in ESPRIT project 937: Debugging and Specification of Ada Real-Time Embedded Systems (DESCARTES).     

Improving the quality of continuous copper rod

Southwire continuous rod technology has been used for approximately a quarter of a century to produce high-quality copper rod, and ongoing modifications to the process have improved not only the copper product, but the actual efficiency of the production system. Some of these developments have been achieved through automatic quality monitoring and the application of sophisticated control devices.     

针对GPON突发模式接收器的低功耗FPGA解决方案

带服务能够支持三重应用（即支持语音、视频和数据）至第一英里的客户，例如持续发展的小商业和住宅。FTTx中的主角是GPON（吉比特无源光网络，Gigabit Passive Optical Network），它提供较高的带宽替代DSL和电缆的基于光纤的网络。FTTx为家庭的第一英里应用，诸如光纤到户（FTTH），     

Risk factors for adolescent substance abuse and dependence: Data from a national sample.

A national household probability sample of 4,023 adolescents aged 12 to 17 years was interviewed by telephone about substance use, victimization experiences, familial substance use, and posttraumatic reactions to identify risk factors for Diagnostic and Statistical Manual of Mental Disorders- (4th ed.; American Psychiatric Association, 1994) defined substance abuse/dependence. Age and ethnicity data were available for 3,907 participants. Major findings were (a) adolescents who had been physically assaulted, who had been sexually assaulted, who had witnessed violence, or who had family members with alcohol or drug use problems had increased risk for current substance abuse/dependence; (b) posttraumatic stress disorder independently increased risk of marijuana and hard drug abuse/dependence; and (c) when effects of other variables were controlled, African Americans, but not Hispanics or Native Americans, were at approximately 1/3 the risk of substance abuse/dependence as Caucasians. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brief group psychoeducation for bulimia nervosa: Assessing the clinical significance of change.

41 women with bulimia nervosa completed a brief intervention that was designed to promote symptom management. Cutoff scores for the determination of reliable and clinically significant change were calculated for several psychometric instruments that are commonly used as outcome measures in the field of eating disorders. Using these statistical procedures to assess therapeutic change, this study documents the diversity of outcomes that individuals reported following their participation in the intervention. As expected, there was a differential reporting of clinically significant change in favor of specific eating psychopathology relative to personality features and associated psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computing eigenvalue bounds for iterative subspace matrix methods

A procedure is presented for the computation of bounds to eigenvalues of the generalized hermitian eigenvalue problem and to the standard hermitian eigenvalue problem. This procedure is applicable to iterative subspace eigenvalue methods and to both outer and inner eigenvalues. The Ritz values and their corresponding residual norms, all of which are computable quantities, are needed by the procedure. Knowledge of the exact eigenvalues is not needed by the procedure, but it must be known that the computed Ritz values are isolated from exact eigenvalues outside of the Ritz spectrum and that there are no skipped eigenvalues within the Ritz spectrum range. A multipass refinement procedure is described to compute the bounds for each Ritz value. This procedure requires O(m) effort where m is the subspace dimension for each pass.     

Low complexity estimation of carrier and sampling frequency offsets in burst‐mode OFDM systems

We study communications under slowly varying channels, and consider three cases of knowledge of the channel impulse response (CIR): full knowledge, no knowledge, and partial knowledge of the CIR. By partial knowledge, we refer to knowing only either the CIR magnitudes or the CIR phases. It is known that obtaining the exact joint maximum‐likelihood estimate (MLE) of the CFO and the SFO requires a two‐dimensional search. Here, we present a new estimation method which uses the Taylor expansion of the MLE cost function, combined with the best linear unbiased estimator, to obtain a method which does not require such a search. The computational complexity of the new method is evaluated. Numerical simulations demonstrate that the new method approaches the corresponding Cramér‐Rao bound for a wide range of signal‐to‐noise ratios, and has superior performance compared to all other existing methods for approximating the solution for the joint MLE, while maintaining a low computational complexity. Copyright © 2015 John Wiley & Sons, Ltd.     

LED产业知识产权问题的思考

随着LED产业迅速发展,使其中埋藏着专利危机,随时威胁着企业利润,文章说明了如何利用专利转危为机,并列举了可能采取的应对策略。