A probabilistic simulator for population dynamics of quasispecies

We constructed a probabilistic simulator that allows all the events in population dynamics such as death, birth, mutation, and suppression/stimulation to be described by probabilistic rules. The simulator also facilitates a lattice used for expressing distribution and diversity (number of distinct strains) of quasispecies. The simulator is used to investigate the diversity threshold in HIV and T-cell interaction. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

电磁搅拌制备ZL12Y铝合金流变半固态浆料的实验及模拟研究

对不同温度及不同搅拌工艺下得到的材料的显微组织的比较，确定了合理的半固态温度和搅拌工艺，即半固态温度为590℃，震荡电流为500A。随后对单个线圈电磁搅拌过程进行建模及电磁场和流速场的耦合模拟得到了电磁场和流速场分布，此结果与电磁搅拌的原理及实验结果相一致。计算出在该温度和工艺下熔体内部的平均流动速度为3．2cm／s，将该结果作为能否得到半固态浆料的判据。     

Modeling dynamic developable meshes by the Hamilton principle

In this paper, a new dynamic developable surface model is proposed. The proposed model represents developable surfaces using triangle meshes. A novel algorithm is proposed to introduce the Hamilton principle into these meshes such that the resulting developable model is dynamic, i.e., it can offer a time-dependent continuous path to deform the model. Applications with examples are presented; these show that the proposed technique can model buckled developable surfaces well, and can offer physically-realistic animations of deformed developable surfaces.     

Pulsating Jet Impingement Heat Transfer Enhancement

This article presents results from a numerical study of pulsating jet impingement heat transfer. The motivation is to seek conditions offering a significant enhancement compared to steady flow impingement drying. The CFD software package FLUENT was used for simulating slot-type pulsating jet impingement flows with confinement. The parameter study included velocity amplitude ratio, mean jet velocity, and pulsation frequency. The distance from nozzle exit to surface was three times the hydraulic diameter of the nozzle. The Reynolds number based on the nozzle hydraulic diameter and jet temperature was 2,460 with a mean jet velocity of 30 m/s, which is the base case of the numerical experiments. Results showed that time-averaged surface heat transfer increased with increasing velocity amplitude for the same mean jet velocity. Large velocity amplitudes helped enhance heat transfer by two mechanisms: high jet velocity during the positive cycle and strong recirculating flows during the negative cycle. For the cases with different mean jet velocities but the same maximum velocity, time-averaged surface heat flux decreased with decreasing mean jet velocity. As for the effects of pulsation frequency, with high-velocity amplitude ratio, time-averaged surface heat fluxes were at the same level regardless of frequency. However, at low-velocity amplitude ratio, high frequency caused stronger recirculating flows resulting in greater heat transfer compared to the cases with a lower frequency.     

Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

空间柔性机械臂三维动力学数值仿真

本文应用ｄ＇Ａｌｅｍｂｅｒｔ－Ｌａｇｒａｎｇｅ原理，对由基座、（ｎ－１）个柔性连杆及端部负载组成，相互用柱铰连接的柔性链式多体系统进行建模；对在空间技术中，具有一刚杆，两柔杆加上刚性负载所组成的三维机械臂系统，采用Ｇｅａｒ算法进行数值仿真。仿真结果比较符合实际，从而在柔性多体系统的数学模型为刚性常微分方程的情况下，为解决其数值仿真问题，特别是三维问题的数值仿真取得了进展。     

一种按时间切换的最速控制方法

基于初始状态空间下的子空间概念，提出了一种按时间进行切换的最速控制方法，不需要求取开关线或开关面。数字仿真结果表明，采用这一方法是完全可行的。     

利用计算机进行油气资源评价和勘探决策

本文着重介绍了构成《现代勘探决策理论系统》的5个主要计算机模块,即:生油岩热演化处理、求任意曲边形面积、数学模拟预测资源量、勘探经济评价分析及决策、辅助处理等模块。该系统曾在塔里木盆地和准噶尔盆地的油气资源评价和勘探决策中发挥了作用,受到了专家和用户的好评。     

Optimal operation of a multibasin reservoir system

A simulation-optimization procedure is presented for evaluating the extent of interbasin transfer of water in the Peninsular Indian river system consisting of 15 reservoirs on four river basins. A system-dependent simulation model is developed incorporating the concept of reservoir zoning to facilitate releases and transfers. The simulation model generates a larger number of solutions which are then screened by the optimization model. The Box complex nonlinear programming algorithm is used for the optimization. The performance of the system is evaluated through simulation with the optimal reservoir zones with respect to four indices, reliability, resiliency, vulnerability and deficit ratio. The results indicate that by operating the system of 15 reservoirs as a single unit the existing utilization of water may be increased significantly.     

Delivering Improvement from Truth — the Fragile Link Between Analysis and Effective Change

In the history of operations research in industry there has been an abundance of analyses and recommendations produced in millions of man hours by dedicated OR specialists. And yet the net improvement is significantly lower than expected. There are numerous reasons for this shortfall: incomplete analysis, too much theory, incomplete implementation, unreliable recommendations, or a combination of some of these reasons.
By describing several examples, the major reasons for the fragility of the link between recommendation and implementation will be reviewed. What has to be done today to increase the likelihood of implementing an OR recommendation and thus improve the performance of an industrial entity by using the power of OR tools will then be described.