Comparison of Linear Level I Green-Naghdi Theory with Linear Wave Theory for Prediction of Hydroelastic Responses of VLFS

Very Large Floating Structures (VLFS) have drawn considerable attention recently due to their potential significance in the exploitation of ocean resources and in the utilization of ocean space. Efficient and accurate estimation of their hydroelastic responses to waves is very important for the design. Recently, an efficient numerical algorithm was developed by Ertekin and Kim (1999). However, in their analysis, the linear Level I Green-Naghdi (GN) theory is employed to describe fluid dynamics instead of the conventional linear wave (LW) theory of finite water depth. They claimed that this linear level I GN theory provided better predictions of the hydroelastic responses of VLFS than the linear wave theory. In this paper, a detailed derivation is given in the conventional linear wave theory framework with the same quantity as used in the linear level I GN theory framework. This allows a critical comparison between the linear wave theory and the linear level I GN theory. It is found that the linear level I GN theory can be regarded as an approximation to the linear wave theory of finite water depth. The consequences of the differences between these two theories in the predicted hydroelastic responses are studied quantitatively. And it is found that the linear level I GN theory is not superior to the linear wave theory. Finally, various factors affecting the hydroelastic response of VLFS are studied with the implemented algorithm.

A NEW CLASS OF LINEAR CODES WITH TWO-LEVEL STRUCTURE

The binary extended Golay code has a two-level structure, which can be used in the decoding of the code. However, such structure is not limited to the Golay code, in fact, several binary linear codes can be constructed by a projective method which is related to the structure. In this correspondence, the binary (4n,n + 2k, ≥min(8, n,2d)) linear codes are resulted from quaternary (n,k,d) linear block codes. Based on the structure, the efficient maximum likelihood decoding algorithms can be presented correspondingly for the derived codes.

Predicting urbanization level by main element analysis and multiple linear regression---taking Xiantao district in Hubei Province as an example

In this paper we firstly select main factors relating to urbanization level of Xiantao District in Hubei Province by main element, then, make model of urbanization level by analysis of multiple liner regression, and lastly predict its urbanization level

A Production Inventory Model of Constant Production Rate and Demand of Level Dependent Linear Trend

The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.

Non-Linear Tank Level Control for Industrial Applications

Tank level control is ubiquitous in industry. The focus of this paper is on accurate liquid level control in single tank systems which can be actuated continuously and modulation of the level setpoint is also required, for example in cascade control loops or supervisory Model Predictive Control (MPC) applications. To avoid common problems encountered when using fixed gain or adaptive/gain scheduled schemes, an accurate technique based around feedback linearization and Proportional Integral (PI) control is introduced. This simple controller can maintain linear performance over the full operating range of a uniform tank. As will be demonstrated, the implementation overhead compared to a regular PI controller is negligible, making it ideal for industrial implementation. Implementation details and parameter identification for adaptive implementation are discussed. Simulations coupled with experimental results using a large-scale laboratory level control system using commercial industrial control equipment validate the approach, and illustrate its effectiveness for both level tracking and disturbance rejection.

Oxygen Isotope Records of Core 8KL of the South China Sea and Sea - level Change

Based on a comparison between the oxygen isotope records of benthic and plank tonic foraminifers from core 8KL of the South China Sea and sea-level change records derived from the Huon Peninsula, New Guinea, it is found that both records are very similar from 72 K a B.P. to the present, especially for the benthic oxygen isotope record. The linear regression shows that δ18O changes (0.9995‰ for benthic foraminifers and 1.022‰ for planktonic foraminifers) are equal to 100 m in sea-level fluctuation. After making temperature correction in the δ18O record of benthic foraminifers from 72 to 120 Ka B.P., the curve of sea-level oscillation of the South China Sea since 186 Ka B.P. has been reconstructed. The lowermost sea - level that occurred in the last glacial maximum and oxygen isotope stage 6 is approximately - 130 m.

THE NUMERICAL SOLUTION OF A SINGULARLY PERTURBED PROBLEM FOR QUASILINEAR PARABOLIC DIFFERENTIAL EQUATION

We consider the numerical solution of a singularly perturbed problem for the quasilinear parabolic differential equation, and construct a linear three-level finite difference scheme on a nonuniform grid. The uniform convergence in the sense of discrete L2 norm is proved and numerical examples are presented.

An analysis on the mean sea level change of the seas adjacent to Korea

Monthly changes of sea level recorded on the seas adjacent to Korea (the Huanghai Sea, the East ChinaSea and the East As) are investigated. The major influences on the spatial and temporal variation of mean sea level arequantitatively identified. A set of modes of monthly air pressure variation over the Huanghai Sea, East China Sea andEast Sea for the period of 1978-1992 is obtained. Each monthly air pressure distribution can be precisely defined bylinear combination of these modes. Hence, the set of air pressure series can be replaced by a set of time varying coefficents, where each coefficient describes the contribution of a particular mode to a given air pressure distribution. A selected set of the modal coefficients is then added to a multiple Fegresion model, consisting of a trend, monthly wind stress and tidal term, in an attempt to represent the effect of meteorological variations on monthly mean sea level on the seas adjacent to Korea. It is found that although the model may account for over 90% of the observed mean sea level variance, there still remains a high correlation between the residuals, hence identifying a regional variation for further study.

Periodic Modulation of Nonlinearity in a Two-Core Photonic Crystal Fiber: A Numerical Investigation

We present a numerical investigation of the propagation and the switching of ultra-short pulses (100 fs) in a two-core nonlinear coupler of photonic crystal fibers constructed with periodically modulated the non-linearity fiber (PMNL-PFC). Our simulations are taking into account different amplitude and frequency modulations of the PMNL-PFC. A coupler for coupling whose length is Lc = 1.8 cm, the transmission characteristics, the compression factor, the crosstalk (Xtalk) and extinction ratio (Xratio) levels of the first order solitons were studied for low to high pump energies considering 2Lc. By an analysis on the reference channel (channel 2), it is observed that at low modulation frequencies an increase occurs in the switching power increasing transmission efficiency. For high modulation frequencies, the transmitted energy efficiency loses. The switching pulses are stronger for low frequency and high amplitude modulation. The Xtalk is a function of the measurement made on the secondary channel (channel 1). It was observed that this unwanted high-frequency energy increases to lessen the measure of the amplitude modulation. In summary, we have demonstrated that introduction of a non-linearity profile takes the periodically modulated PMNL-PFC to strong variations at transmission efficiency, Xtalk, Xratio a function of frequency and modulation amplitude and the input power.

An Alternative Approach for Solving Bi-Level Programming Problems

An algorithm is proposed in this paper for solving two-dimensional bi-level linear programming problems without making a graph. Based on the classification of constraints, algorithm removes all redundant constraints, which eliminate the possibility of cycling and the solution of the problem is reached in a finite number of steps. Example to illustrate the method is also included in the paper.

A Two-Level Purchase Problem for Food Retailing in Japan

In this paper, we deal with a purchase problem for food retailing, and formulate a two-level linear programming problem with a food retailer and a distributer. The food retailer deals with vegetables and fruits which are purchased from the distributer;the distributer buys vegetables and fruits ordered from the food retailer at the central wholesale markets in several cities, and transports them by truck from each of the central wholesaler markets to the food retailer’s storehouse. We solve the two-level linear programming problem in which the profits of the food retailer and the distributer are maximized.

A Water Level Forecast of Pattani River in the Southern of Thailand by Deep Learning

Nowadays, the deep learning methods are widely applied to analyze and predict the trend of various disaster events and offer the alternatives to make the appropriate decisions. These support the water resource management and the short-term planning. In this paper, the water levels of the Pattani River in the Southern of Thailand have been predicted every hour of 7 days forecast. Time Series Transformer and Linear Regression were applied in this work. The results of both were the water levels forecast that had the high accuracy. Moreover, the water levels forecasting dashboard was developed for using to monitor the water levels at the Pattani River as well.

矩阵乘协处理器上BLAS level-3运算的设计

BLAS level-3运算的计算复杂度较高,其往往成为应用的性能瓶颈。采用线性阵列结构的矩阵乘协处理器可实现高性能、高效的矩阵乘运算。在矩阵乘协处理器上高效实现BLAS level-3运算,对大规模科学与工程仿真应用的计算加速至关重要。以矩阵乘为核心运算,结合线性阵列的结构特点,提出了矩阵乘协处理器上BLAS level-3运算的设计,并构建了相应的性能分析模型。实验结果表明,矩阵乘协处理器上SYMM、SYRK和TRMM运算的计算效率分别达到了99%,98%和80%,与SW26010和NVIDIA V100 GPU上矩阵运算的计算效率相比,最高提升了31%。

网络球型摄像机瞬时视场的单点校正水位连续测量方法

基于网络球型摄像机进行洪水监测成为当今水利建设的热点之一,摄像机需进行旋转、焦距的放大与缩小等操作,才能在多视场进行流速、水位、流量一体化监测。由于摄像机传动装置制造的缺陷,在多视场切换时会出现预置点不能准确复位的问题而产生隙动差,这给从单张影像上解析水位、流速造成较大偏差,因此本文提出一种针对水位测量的隙动差校正方法。首先对预置点的水位尺进行精确标定,得到预置点水位方程参数,并在影像上选取两个特征明显的校正点;然后在连续监测中,将瞬时视场内校正点影像坐标按线性方法校正到预置点视场校正点;最后用预置点水位方程参数计算瞬时视场水位。经现场试验测试,不同瞬时视场校正点的影像坐标最大有8像素隙动差,产生水位误差达5 cm,而经本文方法计算的水位误差约为5 mm,说明本文方法对消减隙动差的影响是显著的。

A Lagrange Relaxation Based Approach to Solve a Discrete-Continous Bi-Level Model

In this work we propose a solution method based on Lagrange relaxation for discrete-continuous bi-level problems, with binary variables in the leading problem, considering the optimistic approach in bi-level programming. For the application of the method, the two-level problem is reformulated using the Karush-Kuhn-Tucker conditions. The resulting model is linearized taking advantage of the structure of the leading problem. Using a Lagrange relaxation algorithm, it is possible to find a global solution efficiently. The algorithm was tested to show how it performs.

对中国高校平均学分绩点制度的思考与建议

随着中国高等教育国际化进程的持续推进,源于欧美高校成绩评价体系的平均学分绩点已成为中国高校学业水平评价的主要指标。由于其与学生的评奖评优、免试研究生推荐、境内外升学等切身利益密切相关,从而引发了广泛的关切。针对当前中国高校在课程百分制成绩与绩点的转换方法上存在的利与弊进行了思考,并基于学习成效的科学评价,提出了推动中国高校与欧美高校在学生学业水平评价体系上接轨的建议。

Research on the spectral analysis and testmethod of period signals in monthly mean sea level

This paper summarizes the general methods,existing problems and their causes of the period analysis for the monthly mean sea level and points out that it is the key to the analysing period signals and forecasting the change trend of the monthly mean sea level that the periods of the signals are selected reasonably. As there are often many period signals in these series, nonlinear effects exist between pairs of period signals. In order to avoid the false periods that may be introduced due to the effects of side lobes and the periods with statistical phase significance coherence that may be introduced due to the effects of nonlinear effects and their restraint to other period signals, the maximum entropy spectral analysis and the corresponding significance period test may be performed repeatedly on the basis of the bispectrum analysis and meanwhile the most significant period component is filtered out by the least square filtering method, i. e., the method of the significance period analysis with mixed spectra modeled by a nonlinear system is adopted and the signal periods approaching the reality are selected one by one. The examples of the bispectrum analysis, the signal period analysis by mixed spectra and the fitting parameters for combined period components with linear trend in the time series of monthly mean sea level are given in this paper.

Trend analysis of relative sea level rise or fall of the tide gauge stations in the Pacific

On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The statisticalresults of linear trend Coefficients of these stations indicate that, if the abnormal values of sea-level rise and fall are neglected, the average rise rate of relative sea level in the Pacific is 1. 16 mm/a. Affected by nonuniformity Of land subsidence and other factors, the regional change of relative sea level rise or fall in the Pacific is greater. In the light of thepositive or negative values of linear trend coefficients as well as the geographical position of the sea area, zoning is madeof the sea level rise or fall in the Pacific including the coastal areas of China and Southeast Asia to obtain the averagerate of rise or fall in each sea area. The rise or fall trends of relative sea level obtained for the entire Pacific Ocean,west coast of North America, the northern and central South America, the greater part of the tropical Pacific and thecoastal Islands of Japan are basically in keeping with the other relevant results. The regional average estimated result ofthe relative sea level in the coast of East Asia is on the rise while the estimated results provided by Barnett tend todrop; the main cause of this nonuniformity is the number of stations selected and the distributional density.

数字经济对居民收入的影响效应研究——基于多层线性模型的实证分析

本文基于中国家庭追踪调查微观数据和中国城市统计宏观数据,探讨数字经济与居民收入之间存在的逻辑关系,并运用多层线性模型分析数字经济对居民收入的影响。研究表明:地区数字经济水平对居民收入具有显著正向提升作用,在解决内生性问题以及一系列稳健性检验后结论依然成立;数字经济对不同特征居民的收入影响具有显著异质性,即数字经济会因居民自身特征的不同而对其收入产生不同程度的影响。机制检验结果表明,在数字经济影响居民收入中,居民受教育程度发挥了重要调节作用。结合研究结果,本文提出相关对策建议,以期将数字经济促进居民增收的作用发挥到最大,实现数字经济快速发展和居民收入水平提高的双重目标。

差异化变革型领导对员工安全绩效的跨层次影响

针对差异化变革型领导对安全绩效的影响问题,利用多层线性分析与层次回归分析法,引入心理安全感为中介变量,建立跨层次中介模型。研究表明:团队一致性变革型领导对员工安全绩效具有显著正向影响;个体差异性变革型领导对员工安全绩效具有显著负向影响;心理安全感在团队一致性变革型领导、个体差异性变革型领导与安全绩效间起部分中介作用。团队一致性变革型领导风格能提高员工的心理安全感,从而提高员工安全绩效。