Modern control concepts in hydrology

Two approaches to an identification problem in hydrology are presented based upon concepts from modern control and estimation theory. The first approach treats the identification of unknown parameters in a hydrologic system subject to noisy inputs as an adaptive linear stochastic control problem; the second approach alters the model equation to account for the random part in the inputs, and then uses a nonlinear estimation scheme to estimate the unknown parameters. Both approaches use state-space concepts. The identification schemes are sequential and adaptive and can handle either time invariant or time dependent parameters. They are used to identify parameters in the Prasad model of rainfall-runoff. The results obtained are encouraging and conform with results from two previous studies; the first using numerical integration of the model equation along with a trial-and-error procedure, and the second, by using a quasi-linearization technique. The proposed approaches offer a systematic way of analyzing the rainfall-runoff process when the input data are imbedded in noise

Gender Equality and Women\u27s Issues in Vietnam: The Vietnamese Woman—Warrior and Poet

Exploration of women\u27s issues in Vietnam strengthens the emerging voice of the exotic other female in contemporary international feminist discourse. Any women\u27s movement in Vietnam today must be cast as the revitalization of the Vietnamese woman\u27s collective cultural identity, rather than as a Western imported feminist doctrine. The Vietnamese woman\u27s collective cultural identity is based on the history and cultural folklores of Vietnam, including expressions of feminist ideas in law and literature, and a long history of warfare and collective sufferings, wherein women have been seen as martyrs, national treasures, and laborers in war and in peace. The advocacy of gender equality in Vietnam today is limited by eight risk factors. First, Vietnam\u27s strong matriarchal heritage that persisted through its early history has at times led to the disingenuous proposition that Vietnam has no need for a feminist movement. Second, Vietnam\u27s repetitive, prolonged war and poverty have together overshadowed gender issues. Third, women\u27s movements in Vietnam have not evolved into a doctrine with a structured basis that is independent from nationalism, socialism, or literary movements. Fourth, gender equality in Vietnam has become entangled in what this Article describes as the fallacy of a trio, in which gender equality becomes synonymous with nationalism and socialism. Fifth, the rule of law in Vietnam has traditionally been considered secondary to customs derived from the oppressive values of Vietnamese Confucian society and the autonomy of the Vietnamese agricultural villages. Sixth, women\u27s rights advocacy has been caught up in the universality versus cultural relativism discussion, further complicated by the question of whether there should be Asian-styled gender rights in Vietnam. Seventh, Vietnam, despite its age, is a new nation with a wide variety of philosophical bases, legal traditions, and paradoxical values. Finally, the single-party political system of modem Vietnam renders any feminist movement susceptible to Party politics. The limitations on advocacy for gender equality are illustrated by the shortcomings of Vietnam\u27s Year 2000 National Action Plan, which attempted to address women\u27s issues in the aftermath of the United Nations Fourth World Conference on Women held in Bejing in 1995. While the reassertion of cultural identity can effectively empower Vietnamese women, the feminist advocate must approach cultural identity with caution in order to avoid the semantic traps of euphemism, empty ethnocentricsm, and unhealthy preoccupation with the past that can impede progress for the future. [This article was originally written as the author\u27s LL.M. thesis in conjunction with a seminar on Asia Pacific Legal Community taught by Professor Raul Pangalangan and Professor William Alford, Director of the Center for East Asia Legal Studies, Harvard University.

Stabilization Control of the Differential Mobile Robot Using Lyapunov Function and Extended Kalman Filter

This paper presents the design of a control model to navigate the differential mobile robot to reach the desired destination from an arbitrary initial pose. The designed model is divided into two stages: the state estimation and the stabilization control. In the state estimation, an extended Kalman filter is employed to optimally combine the information from the system dynamics and measurements. Two Lyapunov functions are constructed that allow a hybrid feedback control law to execute the robot movements. The asymptotical stability and robustness of the closed loop system are assured. Simulations and experiments are carried out to validate the effectiveness and applicability of the proposed approach.Comment: arXiv admin note: text overlap with arXiv:1611.07112, arXiv:1611.0711

Distinct order of Gd 4f and Fe 3d moments coexisting in GdFe4Al8

Single crystals of flux-grown tetragonal GdFe4Al8 were characterized by thermodynamic, transport, and x-ray resonant magnetic scattering measurements. In addition to antiferromagnetic order at TN ~ 155 K, two low-temperature transitions at T1 ~ 21 K and T2 ~ 27 K were identified. The Fe moments order at TN with an incommensurate propagation vector (tau,tau,0) with tau varying between 0.06 and 0.14 as a function of temperature, and maintain this order over the entire T<TN range. The Gd 4f moments order below T2 with a ferromagnetic component mainly out of plane. Below T1, the ferromagnetic components are confined to the crystallographic plane. Remarkably, at low temperatures the Fe moments maintain the same modulation as at high temperatures, but the Gd 4f moments apparently do not follow this modulation. The magnetic phase diagrams for fields applied in [110] and [001] direction are presented and possible magnetic structures are discussed.Comment: v2: 14 pages, 12 figures; PRB in prin

Efficiently Clustering Very Large Attributed Graphs

Attributed graphs model real networks by enriching their nodes with attributes accounting for properties. Several techniques have been proposed for partitioning these graphs into clusters that are homogeneous with respect to both semantic attributes and to the structure of the graph. However, time and space complexities of state of the art algorithms limit their scalability to medium-sized graphs. We propose SToC (for Semantic-Topological Clustering), a fast and scalable algorithm for partitioning large attributed graphs. The approach is robust, being compatible both with categorical and with quantitative attributes, and it is tailorable, allowing the user to weight the semantic and topological components. Further, the approach does not require the user to guess in advance the number of clusters. SToC relies on well known approximation techniques such as bottom-k sketches, traditional graph-theoretic concepts, and a new perspective on the composition of heterogeneous distance measures. Experimental results demonstrate its ability to efficiently compute high-quality partitions of large scale attributed graphs.Comment: This work has been published in ASONAM 2017. This version includes an appendix with validation of our attribute model and distance function, omitted in the converence version for lack of space. Please refer to the published versio

Error analysis of ICESat waveform processing by investigating overlapping pairs over Europe

Full waveform laser altimetry is a recently developed method to obtain a complete vertical profile of the height of objects in the footprint as illuminated by a laser pulse. The richness of the signal also complicates the processing. One way to improve the processing strategy is to analyze differences of waveforms that should be very similar because they were obtained at approximately the same time and location. Such waveform pairs are still difficult to find. Here it is shown how to use the archive of ICESat space-borne altimetry data over Europe to determine a set of tenths of thousands of at least partial overlapping waveform pairs. The differences in the values of the waveform parameters, median energy, waveform extent, relative returned energy and intensity distribution are determined and discussed. As a case study, three typical pairs of almost perfectly overlapping waveforms are shown, were considerable differences are still occurring. In all three cases an explanation for these differences is found and discussed. Further analysis of the waveform pairs in this database is expected to considerably improve automatic processing of full waveform data