Range mode and range median queries in constant time and sub-quadratic space

Given a list of n items and a function defined over sub-lists, we study the space required for computing the function for arbitrary sub-lists in constant time.For the function mode we improve the previously known space bound O(n²/logn) to O(n²loglogn/log²n) words.For median the space bound is improved to O(n²loglog²n/log²n) words from O(n²⋅log(k)n/logn), where k is an arbitrary constant and log(k) is the iterated logarithm.     

Prioritizing agile benefits and limitations in relation to practice usage

In recent years, there has been significant shift from rigid development (RD) toward agile. However, it has also been spotted that agile methodologies are hardly ever followed in their pure form. Hybrid processes as combinations of RD and agile practices emerge. In addition, agile adoption has been reported to result in both benefits and limitations. This exploratory study (a) identifies development models based on RD and agile practice usage by practitioners; (b) identifies agile practice adoption scenarios based on eliciting practice usage over time; (c) prioritizes agile benefits and limitations in relation to (a) and (b). Practitioners provided answers through a questionnaire. The development models are determined using hierarchical cluster analysis. The use of practices over time is captured through an interactive board with practices and time indication sliders. This study uses the extended hierarchical voting analysis framework to investigate benefit and limitation prioritization. Four types of development models and six adoption scenarios have been identified. Overall, 45 practitioners participated in the prioritization study. A common benefit among all models and adoption patterns is knowledge and learning, while high requirements on professional skills were perceived as the main limitation. Furthermore, significant variances in terms of benefits and limitations have been observed between models and adoption patterns. The most significant internal benefit categories from adopting agile are knowledge and learning, employee satisfaction, social skill development, and feedback and confidence. Professional skill-specific demands, scalability, and lack of suitability for specific product domains are the main limitations of agile practice usage. Having a balanced agile process allows to achieve a high number of benefits. With respect to adoption, a big bang transition from RD to agile leads to poor quality in comparison with the alternatives.     

Nonlinear robust state feedback control system design for nonlinear uncertain systems

This paper presents a systematic approach to the design of a nonlinear robust dynamic state feedback controller for nonlinear uncertain systems using copies of the plant nonlinearities. The technique is based on the use of integral quadratic constraints and minimax linear quadratic regulator control, and uses a structured uncertainty representation. The approach combines a linear state feedback guaranteed cost controller and copies of the plant nonlinearities to form a robust nonlinear controller with a novel control architecture. A nonlinear state feedback controller is designed for a synchronous machine using the proposed method. The design provides improved stability and transient response in the presence of uncertainty and nonlinearity in the system and also provides a guaranteed bound on the cost function. An automatic voltage regulator to track reference terminal voltage is also provided by a state feedback equivalent robust nonlinear proportional integral controller. Copyright © 2016 John Wiley & Sons, Ltd.     

Role of primate medial vestibular nucleus in long-term adaptive plasticity of vestibuloocular reflex

1. Fifteen hundred and thirty cells were recorded in the medial vestibular nucleus (MVN) of alert monkeys whose vestibuloocular reflex (VOR) had been adapted to one of two kinds of spectacles. The "high-gain" sample was recorded from monkeys that had worn 2.0 x telescopic spectacles; the gain of the VOR in the dark (eye velocity divided by head velocity) was greater than 1.5. The "low-gain" sample was recorded from monkeys that had worn goggles providing a visual field that was fixed with respect to the freely turning head; the gain of the VOR was less than 0.4. 2. Cells showing modulation of firing rate related to imposed head velocity were grouped into four categories: pure vestibular (10), vestibular-plus-saccade (10), vestibular-plus-position (10), and vestibular-plus-head/body (24). Sensitivity to head velocity was measured from averaged responses to sinusoidal, 0.4-Hz whole-body oscillation in the horizontal plane. Almost all cells (98%) having increased firing during ipsilateral head rotation received inputs from the horizontal semicircular canals. Conversely, 82% of cells having increased firing during contralateral head rotation received inputs from the vertical canals. 3. There were no statistically significant differences in resting discharge rate, phase shift, or sensitivity to head velocity between the high- and low-gain samples of any of the cell types. Nonetheless, there was a consistent tendency, evident in all the functionally defined cell groups, for the sensitivity to be about 20% greater in the high-gain samples. However, this difference is small by comparison with the fourfold difference in VOR gain. 4. Detailed scrutiny of the response properties of individual cells suggested that the small differences in sensitivity reflect small changes distributed throughout the population, rather than large and potentially significant changes within a small sub-population. 5. Our data indicate that large, adaptive changes in the gain of the VOR are accompanied by only minor changes in the vestibular sensitivity and no changes in the phase shift or resting discharge rates of cells in the MVN. It remains possible that large changes in vestibular sensitivity occurred in cells we did not sample or in subgroups we could not identify. We argue that this is unlikely and that the major changes underlying VOR plasticity occur after the first central synapse in the VOR pathways.     

Localized eosinophilic granuloma (Langerhans' cell histiocytosis) of the orbital frontal bone

Four patients (aged 5, 8, 14, and 51 years at initial manifestation) with isolated eosinophilic granulomas of the orbital frontal bone displayed short symptomatic periods (two weeks to three months) and some combination of erythema of the lids, a soft, palpable anterior orbital mass, periorbital pain, and osteolytic bone lesions on roentgenography. The bone lesions roentgenographically exhibited irregular, serrated, and sclerotic margins, distinguishing them from the more oval appearance of dermoid cysts. Electron microscopy performed in one case disclosed the presence of Langerhans' granules in the cytoplasm of the histiocytes, indicating that the orbital disease is a mild form of "histiocytosis X" and a benign proliferation of a specific kind of histiocyte--the Langerhans' cell. On follow-up (two to 20 years), after incomplete curettage of two lesions coupled with low doses of postoperative radiotherapy, there was reconstitution of the bone defects, whereas more extensive surgery performed on the other two patients resulted in permanent but subclinical bone defects.     

Stability analysis and state feedback stabilization of pendulum-like systems with multiple nonlinearities

This paper addresses the Lagrange stability analysis problem and the state feedback Lagrange stabilization problem for pendulum-like systems with multiple nonlinearities. An existing method for analysing the Lagrange stability of pendulum-like systems with a single nonlinearity is generalized to pendulum-like systems with multiple nonlinearities. Also, a non-degeneracy condition of the existing Lagrange stability criterion is removed and a strict frequency-domain inequality is used instead. To study the state feedback Lagrange stabilization problem, this paper develops an extended strict bounded real lemma for linear systems which are not stable but stabilizable. A sufficient condition for state feedback Lagrange stabilization is proposed in terms of an algebraic Riccati equation with a sign indefinite solution.     

功率型白光LED的热特性研究

大功率LED照明单元在光通量提高的同时伴随着散热，且普通功率型白光LED多采用蓝光芯片激发荧光粉的方法，随着温度的提升，荧光粉对应的波长会发生漂移。本文从功率型白光LED的发热原理出发，试验了其在脉冲源作用下，用于照明的可能性。试验表明，在此激励源的作用下，LED输出与散热很好，并从理论上进行了解释。     

Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems

The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations.The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modern repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored.     

Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample preparation protocol was developed to enable imaging of cells and gold nanoparticles with a conventional below lens scanning electron microscopes. The negative influence of 'charging' on the quality of scanning electron microscopes' images could be limited by deposition of biological cells on a conductive (gold) surface. The novel protocol enabled high-resolution scanning electron microscopes' imaging of small clusters and individual gold nanoparticles on uncoated cell surfaces. Gold nanoparticles could be counted on cancer cells with automated routines.