Optimal algorithms for trading large positions

In this paper, we are concerned with the problem of efficiently trading a large position on the market place. If the execution of a large order is not dealt with appropriately this will certainly break the price equilibrium and result in large losses. Thus, we consider a trading strategy that breaks the order into small pieces and execute them over a predetermined period of time so as to minimize the overall execution shortfall while matching or exceeding major execution benchmarks such as the volume-weighted average price (VWAP). The underlying problem is formulated as a discrete-time stochastic optimal control problem with resource constraints. The value function and optimal trading strategies are derived in closed form. Numerical simulations with market data are reported to illustrate the pertinence of these results.     

“无障碍”婴幼儿服装设计探略

在介绍＂无障碍＂设计理念的研究基础上,具体分析将＂无障碍＂设计理念引入婴幼儿服装设计的可行性,得出婴幼儿服装＂无障碍＂设计应主要从安全舒适性、实用便捷性、美观性等角度进行,并结合一款婴幼儿连体棉衣的设计实例提出＂无障碍＂婴幼儿服装设计的主张。     

Demonstration plant for seawater desalination by reverse osmosis (RO-2 hollow fibre module line)

A reverse osmosis (RO) seawater desalination demonstration plant (3000 m³/d with three lines) is being operated in Kuwait to investigate the suitability and optimum operating conditions for polyamide hollow fibre compact modules, and spiral-wound modules.The plant described herein has hollow fibre modules with one high pressure stage of 56–63 bar operating pressure and salt passage of about 1.5%, and a second desalination stage with an operating pressure of 28 bar. Drinking water is made up as mixed permeate from the two stages.During the first year, the RO units operated perfectly, and results obtained exceeded the design values.     

基于XML Schema抽象模型的XML模式验证方法

XML模式验证作为处理XML数据的前提和保证有着重要的地位,XML Schema作为XML的定义语言,其本身并不能保证XML数据的有效性.利用XML Schema抽象模型,定义了XML Schema中每个复杂类型的模式信息,并用非终节点序对集描述XML文档,最后给出了XML模式验证算法,可以有效地验证XML文档的组织结构和内容类型.     

Surface and crystalline analysis of aluminum oxide single crystal treated by quasistationary compression plasma flow

Material such as aluminum oxide (Al₂O₃) is important in electronics industry. On the other hand, plasma is one of the most efficient and sophisticated tools for materials processing. In this work a treatment of Al₂O₃ (0001) surface by quasistationary compression plasma flow (CPF) is analyzed in detail. Offline metrology was performed using dielectric measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). Oriented low-dimensional periodic structures are occurred for the plasma treated Al₂O₃ single crystal. In the paper is reported that these oriented ripple-shaped structures contain a higher percentage of oxygen than the surrounding crystal surface. This could be the framework for usage of CPF as a tool in manufacturing of surfaces containing the highly organized oxygen-rich structures.     

细特高密隐格尼丝纺织物的生产

利用全消光和半消光2.22 tex锦纶长丝分别按不同比例搭配作为经纬纱原料,成功开发出一种细特高密隐格尼丝纺织物。较为详细地介绍了隐格尼丝纺织物的产品设计思路,对有关产品的主要生产技术,如整浆并、织造、染整等工序的上机工艺作了重点分析与研讨,并采取了相应的技术措施,从而保证了产品的产量和质量。     

An immunomagnetic-bead-based enzyme-linked immunosorbent assay for sensitive quantification of fumonisin B1

A sensitive enzyme-linked immunosorbent assay (ELISA) based on immunomagnetic beads (IMB-ELISA) was established using a magnetic-bead signal-enrichment system. The immunomagnetic beads were coated with polyclonal antibody directed against keyhole limpet hemocyanin (KLH), which were then coupled with a KLH–fumonisin B1 (FB1) conjugate. Anti-FB1 monoclonal antibody and sample extract were mixed and added to the immunomagnetic-bead solution. After the addition of horseradish peroxidase (HRP)-labeled goat anti-mouse antibody and the substrate solution, stop solution was added and the optical density of the reaction mixture was determined. To improve the performance of this method, the dilution of the immunomagnetic beads, the concentrations of the monoclonal antibody and HRP-labeled goat anti-mouse antibody, and the incubation time for the competition reaction were optimized. Based on the optimum conditions, the regression equation for this IMB-ELISA in quantifying FB1 was y = −0.3538x + 0.703 (R² = 0.9988). The detection limit and IC₅₀ were 0.24 ng/mL and 3.17 ng/mL, respectively. The working range was 0.54–26.3 ng/mL. The recovery rates were 80.4–114.7%, when the spiked concentrations ranged from 19.5 to 156.3 μg/kg. This IMB-ELISA is accurate and more sensitive and less time-consuming than the conventional ELISA.     

Invited general interest paper: Power and propulsion in space

With the development of a manned space station permanently circling the earth, an efficient system is needed to provide both electrical power and propulsion. The electrodynamic tether system being developed by NASA will do this by using a long (e.g. 10 km) conducting tether to interact with the earth's magnetic field. In a low earth orbit, the induced voltage would be on the order of a few tenths of a kilovolt per kilometer of tether. Assuming sufficient electrical contact can be maintained with the ionosphere, a 10 km tether would supply several kilowatts of electrical power. The extraction of power via an associated current results in an I × B force that reduces the orbital speed of the spacecraft. Conversely, if a sufficiently large reverse voltage is applied to reverse the current, then the I × B force will increase the orbital speed and electrical energy will be converted into energy. Consequently, the electrodynamic tether system is expected to perform as a motor/generator system providing a simple, reliable and economical means of efficiently converting orbital energy into electrical energy in a fully reversible process.In addition to a general discussion of the electrodynamic tether system, this article will concentrate on the dynamics of the tether, the proposed electrical contacts or current brushes and the Alfvén waves that will carry the charge through space.     

The level of polyaromatic hydrocarbons in kajal and surma of major Indian brands

Kajal and surma are eye cosmetics extensively used in Indian subcontinent. Kajal is prepared by burning of vegetable oil and butter oil while surma by grinding of the stones. High performance liquid chromatography and gas chromatography–mass spectrometry instruments were used for quantification and confirmation of 16 polyaromatic hydrocarbons (PAHs). Significant concentration of PAH was found in all the samples examined. The median concentration of PAH ranged from 0.14 (lowest, anthracene) to 31.18 μg g⁻¹ [dibenz(a,h)anthracene] in kajal sample and from not detectable concentration (naphthalene) to 197.47 μg g⁻¹ of benzo(a)pyrene in surma sample. Fifteen PAHs were detected in all the samples. Therefore the use of kajal and surma in eye should be strictly restricted.