最大化SLNR及软频率复用的比例公平调度算法

针对 LTE-Advanced 系统中小区间干扰及用户公平性问题,提出了最大化信漏噪比(SLNR)及软频率复用的比例公平调度算法(SLNR–SFR–PF)。该算法通过基于最大化 SLNR的分布式预编码和软频率复用的方法抑制小区间干扰,并结合比例公平调度算法,提高用户的公平性。仿真结果表明,与 SLNR–PF 算法相比,SLNR–SFR–PF 算法使系统容量提高了约7.9%,同时,小区边缘的平均用户数据速率提高了11.5%。     

Spatial reuse efficiency calculation for multihop wireless networks

A multihop network provides an increase in the spatial and frequency resource reuse as compared to a single-hop network. However, a precise quantification of the benefit obtained in terms of spatial reuse is still an open issue. In this paper, a mathematical analysis is carried out in order to derive the spatial reuse efficiency of a multihop wireless network. It is demonstrated through both approximate and exact analysis, that for an unbounded network, the reuse efficiency of the wireless system increases with the number of multiple hops, M  , and the spatial protection margin, Δ$\Delta$, defined around the receiver. Significantly, it has been found that even in case of an infinitely large spatial protection margin, the obtained reuse efficiency is a finite value and is limited by the number of multiple hops in the communicating link.     

软件功能性比对测试方法研究及应用

软件产品质量评价与测试是保障软件产品质量的方式之一。实际工作中,常常需要对多个软件产品进行质量比对,确保获得相对最好的软件产品。随着软件的产品化和软件开发的产业化,软件比对测试逐渐成为产品选型及市场推广的重要工作环节,软件功能性的比对测试也成为客户进行商品化软件选型时的重要依据。本文在GB／T16260系列标准的基础上,提出了软件功能性比对测试的方法,并在实际项目中进行了应用与验证。     

一种基于UML设计的PDM系统可重用性研究

介绍了运用面向对象中的统一建模语言UML设计应用系统的一般过程，以此为基础，对软件重用及其方法作了深入探讨。这种方法可对已有类库进行分析、调整和改进，它是通用的，可应用到产品PDM（Product Data Management）系统等开发项目领域中去。     

Repetitive determination of ascorbic acid using iron(III)-1.10-phenanthroline-peroxodisulfate system in a circulatory flow injection method

Ascorbic acid (AA) could be determined in large quantities of a co-existing oxidant. The incorporation of an on-line reagent regeneration step based on redox reaction eliminates the baseline drift in the procedure. This makes it possible to adopt a circulatory flow injection method (cyclic FIA) and to determine AA repetitively. The method is based on the reduction of iron(III) to iron(II) by the analyte, the reaction of the produced iron(II) with 1,10-phenanthroline (phen) in a weak acidic medium to form a colored complex, and the subsequent oxidation reaction of iron(II) to iron(III) by the co-existing peroxodisulfate. A solution (50 ml) of 3.0×10⁻⁴ mol l⁻¹ ferric chloride, 9.0×10⁻⁴ mol l⁻¹ phen and 5.0×10⁻² mol l⁻¹ ammonium peroxodisulfate in acetate buffer (0.2 mol l⁻¹, pH 4.5) is continuously circulated at a constant flow rate of 1.0 ml min⁻¹. Into this stream, an aliquot (20 μl) of the sample solution containing AA is quickly injected by means of a six-way valve. The complex formed is monitored spectrophotometrically (at 510 nm) in the flow system. The stream then returns to the reservoir after passing through a time-delay coil (50 m). The iron(II)–(phen)₃ complex is oxidized to iron(III)–(phen)₃ complex by peroxodisulfate which exists excessively in the circulating reagent solution. The proposed method allows as many as 300 repetitive determinations of 15 mg l⁻¹ AA with only 50 ml reservoir solution. The contents of AA in commercial pharmaceutical products were analyzed to demonstrate the capability of the developed system.     

Pd(Phen)Cl2 stabilized by ionic liquid: an efficient and reusable catalyst for biphasic oxidative cyclocarbonylation of β-aminoalcohols and 2-aminophenol

Biphasic oxidative cyclocarbonylation of β-aminoalcohols and 2-aminophenol to synthesize corresponding 2-oxazolidinones were investigated in the presence of ionic liquid stabilized Pd(phen)Cl₂ complex. Catalytic comparison results showed that, 1-butyl-3-methyl-imidazolium iodide salts (BMImI) can serve simultaneously as a specific stabilizer to protect the transition metal complex against deactivation, a promoter to increase the catalytic performance and a reaction medium to recycle the catalyst with unprecedented TOF value.     

Synthesis of the ZnO-Ni0.5Zn0.5Fe2O4-Fe2O3 magnetic catalyst in pilot-scale by combustion reaction and its application on the biodiesel production process from oil residual

A magnetic catalyst with composition ZnO-Ni_0.5Zn_0.5Fe₂O₄-Fe₂O₃ was synthesized by a combustion reaction on a pilot-scale and applied in the conversion of residual oil into biodiesel by simultaneous transesterification and esterification reactions (TES). For that, statistical analysis of the factors that influence the process (catalyst concentration, alcoholic route, and temperature) was evaluated by 2³ factorial experimental design. The ZnO-Ni_0.5Zn_0.5Fe₂O₄-Fe₂O₃ magnetic catalyst was characterized in terms of the structure, morphology, magnetic, TPD-NH₃ acidity analysis and catalytic properties. The results indicate the formation of a catalyst with a surface area of 52.9 m²g⁻¹, and density of the sample was 4.8 g/cm³ which is consisted of a mixture of the phases containing 55.87% Fe₂O₃, 36.96% Ni_0.5Zn_0.5Fe₂O₄, and 7.16% ZnO. The magnetic characterization indicated that the synthesized catalyst is ferromagnetic with magnetization 6.12 emu/g and coercive field of 5.3 G. In the TES reactions, the residual oil was active showing conversion to 96.16% ethyl esters and with a long useful life maintaining sustained activity after two consecutive reuse cycles with the conversion of 95.27%, 93.07% and 76.93%, respectively. The experimental design was significant and presented a 95% reliability level. The statistical analysis identified (+1) and (−1) as higher and lower level variables, respectively. The amount of catalyst used was equal to 5%, at 200 °C in methyl alcohol (alcoholic route). In summary, a new catalyst composed of a mixture of magnetically active phases was developed and successfully applied in biodiesel’s synthesis from residual oil. Undoubtedly these results have a positive and significant impact on the environment and to society as a whole.     

Extrusion of poly(vinylidene fluoride) recycled filaments: Effect of the processing cycles on the degree of crystallinity and electroactive phase content

This study analyses the possibility of reprocessing used poly(vinylidene fluoride), PVDF, maintaining the main properties critical for its use in piezoelectric sensor/actuator applications. The influence of multiple reprocessing cycles of PVDF on crystallinity and ß-phase content fundamental for its electroactive behaviour, was studied. Nine reprocessing cycles were completed and it was found that the material preserved the characteristics required for its use as piezoelectric polymer without significant degradation.