新型种鹅自动选育箱设计

种鹅的听觉灵敏、警觉性很强,易受惊吓发生应激反应而改变正常的产蛋的规律。传统的选育种鹅方式是根据鹅的体型外貌,对种鹅分别进行编号登记,在不同的生长发育阶段连续多次进行选择,逐只记录每只鹅的产蛋状况。为了解决传统选育方式的复杂效率低的问题,设计了一种基于电子识别系统的自动育种箱,较于传统选育箱,新型选育箱的最大优点是能够快速确认种鹅个体身份和产蛋情况,并据此淘汰低产种鹅,选育高产种鹅及提高种鹅的品质。     

Three-phase grid voltage synchronization using sinusoidal amplitude integrator in synchronous reference frame

Synchronization with the grid voltage is critical in the control of grid-connected power converters. Under unbalanced grid condition, the conventional synchronous reference frame phase-locked loop (SRF-PLL) does not work well due to the effect of the fundamental negative sequence component. This paper proposes a new synchronization method, the sinusoidal amplitude integrator based phase locked loop (SAI-based PLL), to efficiently eradicate the effect of the fundamental negative sequence component. As a result, it can accurately and quickly estimate the amplitude and phase angle of the fundamental components of grid voltages in unbalanced grid conditions. In addition, when dc offset and harmonics are contained in the grid voltage, a multi-SAI-based PLL method is developed to extract the synchronization signal. The proposed SAI-based PLL incorporates the sinusoidal amplitude integrator into the conventional SRF-PLL. Its operation is analyzed using the complex-vector notation. Simulation and experimental results on the performance of the proposed SAI-based PLL and comparison with other synchronization methods are presented.     

模式识别自动相分析探讨与系统实现

本文结合自动测井相分析的问题，实现了自动相分析系统，并用聚类算法分析测井相与岩相的对应关系建立岩相库。文中分析了测井数据的特征提取、数据白化等关键问题，给出的模式识别具有自动筛选变量的功能。本文的方法应用于实际，取得了良好的效果。     

高海拔条件下选择实用型水稻光温敏雄性核不育系的可行性研究

以湖北省远安县苟家垭镇窑河村（北纬３１°１３′，东经１１１°２′，海拔５２５～５４０米）作为长日低温环境，进行了实用型水稻光温敏核不育系的选择和鉴定研究。参试材料有光敏型不育系ＮＫ５８Ｓ，低温敏型核不育系培矮６４５、ＨＮ５Ｓ和高温敏型不育系Ｗ６１５４Ｓ５、Ｗ８０１３Ｓ。试验方法是进行分期播种、连续观测小穗自交不育度，并同步观测气温。早稻类型的品种４月上旬播种，７月中旬可以齐穗，中、晚稻品种４月下旬播种，８月中、下旬可以齐穗。高温敏型的不育系在该点无明显的不育期，自交不育度在８０％左右，低温敏型的不育系基本保持稳定的不育。光敏型的ＮＫ５８Ｓ，敏感期处在２４℃以上时表现不育，２４℃以下时表现基本可育。当温度在２４℃上下波动时，育性也随之出现波动。研究结果初步认为，该点作为长日低温选择环境是可行的。早稻类型的材料可在７月中旬和８月中、下旬选择和鉴定，中、晚稻类型的材料可在８月中、下旬选择和鉴定。     

Modal Identification Algorithm with Unmeasured Input

This paper investigates the possibility of generating a time‐domain modal identification algorithm that does not need measurements of the input signals. Such a technique is useful when complete input data acquisition cannot be performed. The approach is based on the Yule‐Walker equations, extended to the case where the input signal is not white noise. The algorithm is written recursively both to minimize data acquisition and to be flexible enough when time‐varying modal parameters are tracked. Natural frequencies and damping ratios are extracted with an error magnitude inferior to impulse response techniques but superior to methods using the input time history. From a computational aspect, the algorithm only introduces scalar inversions, which presents an important gain of time and stability. Examples and comparisons with other techniques are presented. The case where a change in the modal parameter values occur is also highlighted. A normalized error, taking into account the quality and the swiftness of the new estimation, is introduced.     

Cyclic control of water quality in a tidal river segment

This paper suggests a simple method for maintaining a desired level of dissolved oxygen in a tidal river. The scheme takes advantage of the short time periodic tidal nature of the river in the utilization of the ability of the river to assimilate biological oxygen demand loading. The parameters of the river model are determined on-line using a Powell search to process actual river data. After model parameter identification, the Powell search is again applied to find the parameters of the control effort to be applied to the cyclic control of reaeration effort and BOD discharge into the stream. Identification of the model parameters requires measurements of only BOD and DO. Because the system is designed to keep the model up-dated in the short term sense, it also implicitly accounts for the usual long term influences. The modelling procedure was tested against data obtained from the Penobscot River in Maine, and the control strategies were tested on the river model simulation.     

走自动识别和认证的多元化之路——谈当前RFID的“分流”和“统合”

RFID的“过热”容易引起业内的“窘困”和事与愿违的“衰败”因素。本文在列举和介绍了两种国外正在发展的相关技术之后,指出向RFID周边技术“分流”的必要性和可能性。本文介绍了外国政府在RFID业内采取支持重点的举措,发表了中国政府的管理部门要把重点支持项目统合到关键技术上来的观点。     

Improving an adaptive controller for non-minimum phase plants

This study improves an adaptive controller for linear discrete-time plants in two aspects: (1) a new adaptation law is proposed to reduce the residual and the parameter errors; (2) a new method is proposed to modify the parameter estimates if the estimated model is not controllable. The second improvement is required when the plant is non-minimum phase. It obtains a controllable model from available parameter estimates while minimizing the modification offset. These features enhance closed-loop tracking performance of the adaptive controller when it is applied to non-minimum phase plants.     

Estimation of an N-L-N Hammerstein-Wiener model

Estimation of a single-input single-output block-oriented model is studied. The model consists of a linear block embedded between two static nonlinear gains. Hence, it is called N-L-N Hammerstein-Wiener model. First, the model structure is motivated and the disturbance model is discussed. The paper then concentrates on parameter estimation. A relaxation iteration scheme is proposed by making use of a model structure in which the error is bilinear-in-parameters. This leads to a simple algorithm which minimizes the original loss function. The convergence and consistency of the algorithm are studied. In order to reduce the variance error, the obtained linear model is further reduced using frequency weighted model reduction. Simulation study will be used to illustrate the method.     

微机频率响应辨识仪的设计调试与应用

一、前言建立数学模型可用理论方法和实验方法,或用二者结合的方法.本文采用频率响应法(山下法)设计辨识仪,即由已测出的系统频率特性来拟合传递函数,从而建立起系统数学模型. 二、微机频率响应辨识仪的工作原理微机频率响应辨识仪的原理和框图如图1所示.由频率特性测试仪产生一系列不同