基于窄带电力噪声干扰的OFDM分组检测算法

针对电力噪声和正交频分复用(orthogonal frequency division multiplexing,OFDM)信号的特点,为提高检测的准确度同时减少数据冗余,基于含噪信号本元分析,分解干净信号和电力噪声特征向量,根据噪声和信号空间能量的不同,利用本元滤波的方法检测数据分组的起点。在电力噪声和基于G3方案的OFDM模型下,通过对经典延时相关检测算法和本元滤波检测算法进行性能评测比较,结果显示在不同信噪比下,本元滤波检测算法对接收信号的起点检测更准确,相应系统的误码率得到降低。

Parameter fitting of constitutive model and FEM analysis of solder joint thermal cycle reliability for lead-free solder Sn-3.5Ag

The experimental tests of tensile for lead-flee solder Sn-3.5Ag were performed for the general work temperatures range from 11 to 90 ℃ and strain rate range from 5 × 10^-5 to 2 × 10^-2s^-1, and its stress--strain curves were compared to those of solder Sn-37Pb. The parameters in Anand model for solder Sn-3.5Ag were fitted based on experimental data and nonlinear fitting method, and its validity was checked by means of experimental data. Furthermore, the Anand model was used in the FEM analysis to evaluate solder joint thermal cycle reliability. The results show that solder Sn-3.5Ag has a better creep resistance than solder Sn-37Pb. The maximum stress is located at the upper right comer of the outmost solder joint from the symmetric center, and thermal fatigue life is predicted to be 3.796 × 10^4 cycles under the calculated conditions.

AIDS Treatments Efficiency Analysis Based on Cost Efficiency Data Envelopment Analysis Model

Three data envelopment analysis (DEA) models were used to analyse the relative efficiencies of four AIDS treatments in AIDS Clinical Trial Group (ACTG) Study 193A(1 309 patients in total, classified into 4 age groups). Results from the output-oriented BCC model show that Treatment 4 ( 600 mg of zidovudine plus 400 mg of didanosine plus 400 mg of nevirapine) is particularly efficient for age group 14—25, but not efficient for the older age groups; Treatment 1 (600 mg of zidovudine alternating monthly with 400 mg of didanosine)and Treatment 2 (600 mg of zidovudine plus 2.25 mg of zalcitabine) are efficient for the age groups 35—45 and 45— ; age group 25—35 does not have a particularly efficient treatment, but Treatments 1 and 2 are relatively good. The cost efficiency BCC model, which takes the treatment cost into account, gives similar results as the output-oriented model. Results from the indirect output-oriented BCC model, which allows the replacement among medicines, show that the efficiency of Treatment 2 has greatly decreased compared with that of the output-oriented model, and a set of optimal medicine amounts for different age groups is obtained.

Generic Transgression of Tragicomedy in Anton Chekhov＇s The Seagull and George Bernard Shaw＇s The Apple Cart

This paper delves into Anton Chekhov＇s The Seagull and George Bemard Shaw＇s The Apple Cart to extensively analyze their infusion of certain comical elements in depicting ostensibly tragic concerns. The paper aims at exploring the use of the comic elements that is not without purpose. Instead through this incorporation of farce, linguistic humor, witty repartee and exaggeration, the holistic vision of life is obtained which was earlier compartmentalized by the Greeks and Roman playwrights. Comic elements including slapstick humor, the singing of songs, and certain character portrayal are discussed as techniques employed at the hands of the playwrights to reflect over the real historical milieu of their respective times, yet giving a boost to realism as a theory and a practice. This is a qualitative study based upon hermeneutic theory of textual analysis. The paper establishes the similarities in Bernard Shaw＇s and Anton Chekhov＇s employment of comical elements as well as the difference between their essential purposes in generic transgression. Although the two writers have their roots in different countries, their humorous portrayal of various issues is seen to be similar. From the microanalysis of these plays, the same comic strains can be traced out in modern drama at macro level that will enhance the implication of this research paper. This paper therefore concludes that comic and tragic elements are not antagonistic rather complimentary to each other.

Analysis of telescopic beam structure using couple of DOF technique and its application

Couple of DOF technique in FEM and the algorithm for equation group solution in the whole stiffness matrix is studied in this paper. A new procedure is developed for the analysis of telescope beam structure. This method can solve most of the complex structural problems in engineering practice. This method has been used in the FEM analysis of pile frame of muhifunetion drilling machine, which is designed and manufactured by our research group. The right analysis result can improves the design efficiency and the reliability of the structure and reduce the design cost.

Using Magnetic Barkhausen Noise Technology and Finite Element Method to Study the Condition of Continuous Welded Rails on the Darwin-Alice Springs Line

The Magnetic Barkhausen Noise （MBN） technology is a non-destructive method to measure the neutral temperature of thc CWR track. A series of in-field verifications and data comparison on Australian mainline tracks have shown the results from that system are highly accurate and reliable. The system can be an accuracy and cost-effective tool to prevent the potential buckling and break of CWR rails. The physical backgrounds and features of the system are represented in this paper. The Darwin-Alice Springs Line is a newly constructed main line in Australia which is linked from the north and middle of Australia. Originally, this rail line is designed and constructed in a ＂cost-effective＂ way to a lower price, and the key parameters are relatively low. To maintain the stability of the CWR tracks in a very harsh environment, some new technologies such as the MBN technology were utilised. From the results of neutral temperature, it is found that the majority of them are very high. Combined with the calculation and finite element analysis, these problems evidenced that it is caused by the low toe load fastening system and high sleeper spacing. After that some suggestions are given to improve the stability of the CWR on the railway line.

Intellectual Capital, Corporate Culture and Performance of Firms Listed on Nairobi Securities Exchange

The broad objective of this study was to establish the moderating effect of corporate culture on the relationship between intellectual capital and organizational performance of firms listed on Nairobi Securities Exchange. The review of literature provided conceptual and empirical gaps that formed the basis of the conceptual hypotheses. Two hypotheses were deduced from general objective： Intellectual capital has a significant influence on corporate performance; corporate culture moderates the relationship between intellectual capital and corporate performance. A cross-section research design was adopted. A survey questionnaire was the main tool of data collection and was distributed to the 50 heads of human resource departments in the different firms＇ period covering four financial years from 2009 to 2012. The study also utilized secondary data obtained from Capital Market Authority Statistical bulletins and Nairobi Securities Exchange Handbook 2012-2013 to collect data on financial performance （ROA, ROE, and Dividend Yield）. Data were tested for reliability results showing that study dimensions were reliable, apart from task-oriented culture that had a Cronbach alpha of 0.262, thus being not considered for further analysis; thus the study relied on employee-oriented culture as a measure of corporate culture. The hypotheses were tested using multiple regression analysis and hierarchical regression respectively. Multiple regression analysis showed that intellectual capital had a significant influence on non-financial performance and no significant influence on financial measures of performance （ROA, ROE, and Dividend Yield）. Test for moderation showed that the interaction term was not significant and thus, employee-oriented culture did not moderate the relationship between intellectual capital and corporate performance. The study demonstrates importance of the influence of intellectual capital on non-financial performance of firms listed on Nairobi Securities Exchange. The results show that interplay among human capital, social capital, and organization capital is important for firms listed on Nairobi Securities Exchange and that the firms should nurture the employees into sharing their knowledge by creating internal and external networks and also creating support system within the organization to retain the knowledge.

Computational Fracture Analysis of an AFM-Specimen under Mixed Mode Loading Conditions

Fracture processes in ship-building structures are in many cases of a 3-D character. A finite element （FE） model of an all fracture mode （AFM） specimen was built for the study of 3-D mixed mode crack fracture behavior including modes Ⅰ,Ⅱ, and Ⅲ. The stress intensity factors （SIFs） were calculated by the modified virtual crack closure integral （MVCCI） method, and the crack initiation angle assessment was based on a recently developed 3-D fracture criterion--the Richard criterion. It was shown that the FE model of the AFM-specimen is applicable for investigations under general mixed mode loading conditions, and the computational results of crack initiation angles are in agreement with some available experimental findings. Thus, the applicability of the FE model of the AFM-specimen for mixed mode loading conditions and the validity of the Richard criterion can be demonstrated.