An improved parameter estimation procedure in lake modelling

This paper proposes an alternative parameter estimation procedure. Usually the parameters that yield the highest sensitivity are calibrated by trial and error or by an automatic calibration procedure. If the number of parameters to be calibrated is more than 3-5, this procedure is very time consuming. The presented procedure is based on the assumption that the biological components in an ecosystem model attempt to develop such properties that they become best possible survivors, i.e. develop as much biomass as possible. It has previously been proposed that the survival of the entire ecosystem can be measured by use of the thermodynamic function exergy, which measures the distance from thermodynamic equilibrium and accounts for the biomass and its information content. If these assumptions are correct, it should be possible to determine the combination of parameters which gives the highest exergy. The paper presents the use of this idea in combination with a normal calibration. The parameters, which are less known from the literature and still yield a relatively high sensitivity, are determined by use of the above-mentioned exergy principle. The parameters that are known within relatively narrow ranges from the literature are calibrated by the normal procedure. The method has been used on a concrete lake modelling study and given good results. This combination method seems therefore to offer clear advantages, particularly for models with a relatively high number of sensitive parameters (> 5), which otherwise would require a very cumbersome calibration.     

Unity direct chain with feedback series impedance based innovative negative group delay circuit

An innovative negative group delay (NGD) circuit theory on unity direct chain (UDC) topology is developed in this paper. The NGD UDC cells are based on the operational amplifier adder with feedback series impedance. Innovative topologies of high-pass NGD UDC cell composed of RL-series network, all-pass RC-parallel network and low-pass RC-series network are identified. It is a first time that all-pass NGD original topologies are defined. NGD analyses and synthesis methods of each NGD UDC cells are provided. The UDC cell based NGD functions are validated with SPICE simulations. The proofs-of-concept (POC) of UDCs behave as all-pass and low-pass NGD functions with group delay equal to −1 ms at very low frequencies. The low-pass NGD cut-off frequency is 424 Hz. The high pass NGD circuit generates −1 µs at the optimal NGD frequency of about 5.15 kHz. Further analysis of the operational amplifier gain and bandwidth effects is performed. The operational amplifier gain affects significantly the NGD level and bandwidth for the all considered UDC cells. Nevertheless, only the RC-parallel feedback based UDC cell is particularly sensitive to the operational bandwidth.     

Robust techniques for abandoned and removed object detection based on Markov random field

This paper presents a novel framework for detecting abandoned objects by introducing a fully-automatic GrabCut object segmentation. GrabCut seed initialization is treated as a background (BG) modelling problem that focuses only on unhanded objects and objects that become immobile. The BG distribution is constructed with dual Gaussian mixtures that are comprised of high and low learning rate models. We propose a primitive BG model-based removed object validation and Haar feature-based cascade classifier for still-people detection once a candidate for a released object has been detected. Our system can obtain more robust and accurate results for real environments based on evaluations of realistic scenes from CAVIAR, PETS2006, CDnet 2014, and our own datasets.     

Optimisation of combined collaborative recommender systems

A new approach to collaborative user modelling is presented in this paper. We have developed a framework that can be used for easy testing of different concepts. We have also introduced three different areas where collaborative modelling can be further improved. For the first phase of testing, we have created a hybrid system based on three different collaborative recommender techniques. Since this system implements multiple collaboration techniques, we decided to call this approach Combined Collaborative Recommender. Although each prediction technique can produce adequate results, we have proved that the combination of these techniques into a unified system provides a much more stable system. It should also be pointed out that these analyses were done using a very large dataset (more than 2 million ratings) providing reliable results. Results of these optimisations are presented along with pointers for further development.     

Inrush current estimation and hot-swapping for safe parallel battery pack

ABSTRACT

Batteries used in electric vehicles and microgrid applications use battery modules connected in series to satisfy the voltage required for each system, and battery modules are connected in parallel to increase capacity. In this parallel connected system, in order to disconnect and reconnect a specific battery module or to reconnect a new battery module, the battery module to be newly connected should have a small state of charge (SOC) difference from the existing battery modules. In particular, when a new battery is to be connected under a load current, there is a problem that excessive inrush current may occur in a specific battery module due to the load current distributed to each module and the current due to the SOC difference. Therefore, in this paper, we propose a method of estimating the inrush current through an equivalent electrical modelling analysis for the case where a battery module is newly added in a system in which the battery modules are connected in parallel. In addition, the power management algorithm for the battery pack system with inrush current estimation is presented. The proposed method is validated through simulations and experiments of a battery pack system in which 10 battery modules of 710V and 120Ah are connected in parallel.     

关于科技馆发展趋势和特点的思考

从我国和世界的科技馆发展现状,科技馆的建设内容、展教手段、整体建设、社会使命、管理体制以及项目规划和选址等方面阐述了作者对科技馆发展趋势和特点的思考。     

神府东胜矿区沙漠化的现状及趋势

在野外调查、沙漠化制图及资料计算的基础上，对矿区沙漠化的现状及趋势进行了分析，结果表明，矿区现有沙漠化面积2457.0km^2，占总土地面积的64.0％，其中轻度1120.0km^2，中度531.4km^2，强度805.6km^2。煤田开发前沙漠化“自然”增长速度为0.5%。开发前期（1998年－1991年）受建设施工活动影响，沙漠化增长速度0.95％，为开发前沙漠化“自然”增长速度的1.90倍，开发后期（1992年－2006年）建设施工活动仍然频繁，地面塌陷和地下水位降落日益加剧，沙漠化增长速度将达1.18%，为开发前沙漠化“自然”增长速度的2.36倍，沙漠化增长趋势明显，应引起有关方面的重视。     

论现代双线干油集中润滑系统的高压化趋势

本文论述了双线干油(脂)集中润滑系统的发展简史和现代高压双线干油集中润滑系统,并对低压(138bar)、中压(210bar)和高压(400bar)系统的管路内润滑脂滞留时间及它们的综合投资费用和经济性等进行了分析比较,阐明了其高压化趋势的原因。