Normalized transfer function for characterizing conversion efficiency and harmonic distortion of all-optical sampling

A novel method for characterizing the nonlinearity of all-optical sampling is proposed based on the normalized transfer function.Simulation results demonstrate the effectiveness of our method.Furthermore,an all-optical sampling experiment is performed to verify our method.Both simulation and experiment show consistency between our method and the measurements.The method only requires normalization and polynomial fitting of the transfer curve,and enables direct expression of the nonlinearity with the coefficients of the normalized transfer function.     

工程师的现场管理—指令的使用

现场指令，作为解决工程施工过程中遇到的问题，而采取的一种处理形式现场指令的发布既要及时，又要慎重：既要有利于施工的方便快捷，又要尽量减少因此而引起的合同纠纷     

一类高新技术公司风险预测指标分析及评估方法

以管理顾问及咨询公司为背景,来探讨高新技术公司的风险.在分析可能产生的风险基础上,建立风险预测指标体系,并给出风险评估的方法.     

Performance analysis of optimal channel estimation and multiuser detection in a randomly-spread CDMA channel

<正> This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical mechanics.The authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system loads.Our results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions.     

Performance comparison of distributed state estimation algorithms for power systems

A newly proposed distributed dynamic state estimation algorithm based on the maximum a posteriori (MAP) technique is generalised and studied for power systems. The system model involves linear time-varying load dynamics and nonlinear measurements. The main contribution of this paper is to compare the performance and feasibility of this distributed algorithm with several existing distributed state estimation algorithms in the literature. Simulations are tested on the IEEE 39-bus and 118-bus systems under various operating conditions. The results show that this distributed algorithm performs better than distributed quasi-steady state estimation algorithms which do not use the load dynamic model. The results also show that the performance of this distributed method is very close to that by the centralized state estimation method. The merits of this algorithm over the centralized method lie in its low computational complexity and low communication load. Hence, the analysis supports the efficiency and benefits of the distributed algorithm in applications to large-scale power systems.     

Simulation study of SVM-based approach in extracting parameters for electromagnetic detection of buried object

In this paper, a new method for extracting the parameters of buried object is proposed. The center position and dielectric properties of 2-D buried object are estimated by means of a regression technique based on support vector machine (SVM). The proposed method, after a proper training procedure, is able to reconstruct the center position and dielectric properties of a buried object inside a given investigation domain. Numerical simulation results indicate that SVM-based approach shows higher accuracy than the back-propagation neural networks (BPNN) algorithm.     

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.     

Research and Reflection: Potential Impact on the Professional Development of Undergraduate Occupational Therapy Students

In occupational therapy education in South Africa, community service (CS) focuses learning opportunities during fieldwork placements. CS therefore enabled the researcher to utilise successive small scale research projects to guide learning of students during fieldwork while simultaneously developing the occupational therapy service at a residential care facility. This community setting provided a powerful environment through which research, in combination with opportunities for reflection, contributed to nurturing skills needed by these future health professionals. A technical action research (AR) approach incorporated AR cycles and opportunities for structured reflection. Therefore situations were created for the students to embrace experiential learning. Experiential learning in the form of anticipatory reflection, reflection-in-action, reflection on reflection and retrospective reflection impacted on the quality of the students’ work. Besides encouraging unique leaning opportunities for students when engaging in research during their fieldwork placement, engagement in AR cycles simultaneously improved service delivery to residents in the facility. Key benefits of this investigation were that fieldwork education utilising AR cycles within a CS situation promoted students to identify voids in their theoretical background as well as practice skills; to apply reflective practice that could contribute to their personal and professional development; and to utilize learning opportunities optimally. Despite positive gains showed by this study, the role of power relations between the researcher as fieldwork educator and the students prohibited the AR cycles from being more emancipatory in nature and should be addressed in follow-up studies.     

Multilevel Innovation in Remote Networked Schools

Small remote rural schools in Quebec face an ongoing challenge to provide similar quality educational services than bigger schools. Since 2002, the Remote Network Schools (RNS) initiative afforded schools the opportunity to reinvent their practice by using online tools to experience collaborative learning activities with other remote schools. Teachers and students experienced quality learning and demonstrated agency by implementing the RNS in their context. Measures include: diversity of learning activities, quality of online classroom interactions, changes in teacher beliefs, and shifts in teacher and student roles. Our results show that it is a viable operating method for such schools and that other schools could contemplate implementing such innovative practices.     

Texture preserving denoising method combining total variation and wavelet shrinkage

In this paper,we propose a new image denoising method that combines total variation(TV) method and wavelet shrinkage. In our method,a noisy image is decomposed into subbands of LL,LH,HL,and HH in wavelet domain. LL subband contains the low frequency coefficients along with less noise,which can be easily eliminated using TV-based method. More edges and other detailed information like textures are contained in the other three subbands,and we propose a shrinkage method based on the local variance to extract th...