Development of grain threshers based on ergonomic design criteria

Threshers are used extensively on Indian farms for threshing grains, but are involved in a significant proportion of limb crush injuries. International safety standards are somewhat difficult to enforce because manufacture of machines is done at widely dispersed local workshops. Locally made machines are used for crop production and post-harvesting operations, with a great deal of manual work. This technical note reports the results of a study to develop a cost effective, improved design for safe operation of threshers based on ergonomic principles.     

PWB装配线综合生产能力计划模型及其近似求解算法

提出了多产品柔性制造环境中市场需求确定动态且完全由生产满足的条件下PWB 装配线的再设计模型.由于该模型为大规模混合整数规划问题,提出了一种首先求解若干递 归线性规划以减小搜索空间,然后应用启发式搜索的近似求解方法.实际问题的计算结果表 明了所提出算法的有效性.     

Ergonomic design of large forestry machines

Since 1967, the ergonomic design of large forestry machines has been the subject of continuous study. Ergonomic guidelines have been developed and successfully introduced to the manufacturers of the machines and to the forest industries.

Manufacturers have implemented comprehensive ergonomic improvements. Operator workspace, visibility, lighting, operator's seats, mounting and alighting, cab climate, and service of machines have been improved. Noise and vibration levels have been reduced. The risk of accidents is slight. In many respects, the ergonomic standard is now good.

Increasing mechanization is posing new problems, however. Operators of forestry machinery are being afflicted by overload injuries to the neck, arms, and cervical spine. The main causes of these injuries are probably excessive periods of sitting, excessive work intensity during work in fixed, ergonomically inappropriate positions, and repetitive, short-cycle movement patterns. Ergonomic improvements in equipment design (particularly controls) and work organization are proposed in this report.     

Performance analysis of manufacturing systems composed of modular machines using the universal generating function

The modularity and reconfigurability of the building blocks of modern manufacturing systems have to be considered when evaluating their performance. This paper proposes a model for evaluating system availability and expected production rates for manufacturing systems that are composed of unreliable modular machines with multiple functionally parallel production units. These units are treated as independent modules, where the breakdown/stoppage of one unit does not necessitate the failure/stoppage of the whole machine and its production. The considered systems are multi-state manufacturing systems (MSMS) that can handle multiple parts simultaneously, and their structure is that of nonbuffered flow lines allowing paralleling of identical multi-state modular machines (MSMM) in each production stage. In spite of the inherent computational complexity of the proposed analysis, due to the large number of system states, it was made possible by the use of the universal generating function (UGF) technique, which proved efficient for large MSMS. The proposed model was applied to a number of case studies for demonstration and verification. The case studies were based on a family of engine front covers. The results show that machines with a larger number of modules, usually thought of as having lower availability, provided higher overall system availability in the case of machines with multiple spindles. Based on the new analysis and results, it is recommended that system designers favorably consider machines with multiple spindles rather than increasing the number of machines in parallel. These results provide an important support for the use of modular/reconfigurable equipment compared with traditional equipment, in spite of the higher cost.     

基于运动想象辅助的下肢康复控制系统

现今社会中由于种种因素，如自身机能下降、意外车祸、外伤等造成的肢体运动性障碍的病人在显著增加。临床上广泛使用下肢康复训练机器来辅助患者康复训练，而近年来脑机接口技术的飞速发展，使其在该康复领域得到极大的重视。脑机接口通过对肢体运动障碍患者运动想象或诱发产生的脑波信号进行识别，从而控制下肢康复设备实现辅助运动。     

Green IT More Than a Three Percent Solution?

IT infrastructure is definitely going green. From significant new regulations for IT equipment disposal to stringent energy-efficiency specifications for PCs and monitors to national standards for data center power savings, Green IT is an "in" topic. But many problems are unsolved. Will telecommuting make a difference or is it too difficult to manage? Will cloud computing reduce the number of large data centers? Can legislation diminish e-waste challenges?     

Human centered design methodology: Case study of a ship-mooring winch

This paper proposes a human centered design process for the marine industry to support naval architects and marine engineers in the integration of human element considerations in the design of ship systems. The proposed Human Centered Design methodology derives from codes and standards, including those for equipment certification. A case study, consisting of the design of a mooring winch and control station, is developed to illustrate the proposed approach. The referred case study is selected since a significant number of fatal accidents and severe injuries occur during mooring operations. Furthermore, the results of a human centered intervention on the identified deficiencies should be easily perceived by industry stakeholders, thereby increasing the stakeholder's willingness to integrate the human element in systems design. To this end, design deficiencies identified in the mooring workspace and control station of a containership are first presented. Afterwards, two control panel layouts are recommended following the proposed Human Centered Design approach. A preliminary assessment of the control panel layouts regarding their compliance with existing standards and guidelines is carried out. Additionally, this study indicates that mooring workspace and equipment design deficiencies are related to the limited deck space, which is primarily maximized for ship cargo.     

Anthropometric study of Algerian farmers

An anthropometric study of Algerian date-palm farmers was carried out. Thirty-six body dimensions were measured. Mean, variation measures, percentiles, 4 indices, and correlation coefficients between body dimensions were calculated. Effects of age were studied. Data of Algerian farmers and farmers from both developed and developing countries are compared. Body dimensions results were presented in one table so that they can easily be used by designers. It has been found that both stature and weight correlated significantly with many body dimensions. In addition, age was found to affect body height and weight. Moreover, it was found that stature and weight have increased with time. These days farmers are taller and heavier than farmers of the 1960s. Algerian farmers are also taller and heavier than farmers of many developing countries. However, when Algerians are compared with the farmers of developed countries, they are shorter and lighter.

Relevance to industry

The physical dimensions of the workplace are very important because small changes can have a considerable impact on worker health, safety, and productivity. Therefore, this study was completed to provide anthropometric data that can be used to design or redesign agricultural machines, tools and equipment. Date-palm agriculture is still done traditionally in most of the date-palm producing countries. The introduction of ergonomically designed technology will improve the date-palm industry.     

开工时间延迟下的炼钢-连铸生产重调度方法

在炼钢-连铸生产过程中, 因铁水或废钢供应不及时经常发生钢水在转炉设备上开工延迟, 导致相邻炉次在同一设备上产生作业冲突或同一浇次内的相邻炉次在连铸机上断浇, 使原调度计划失效.由于炼钢-连铸生产存在多台转炉、多台精炼炉和多台连铸机, 以及多重精炼方式且存在着可重入生产情况, 加上要保证已开工和完工炉次按原调度计划执行, 使得已有炼钢-连铸生产重调度方法难以适用.本文建立了开工时间延迟下的炼钢-连铸生产重调度模型, 将模型分解和启发式方法相结合, 提出了由炉次加工设备指派和作业时间决策组成的启发式重调度方法.通过实际工业数据仿真实验和在某大型钢铁企业的炼钢-连铸生产重调度的工业应用表明所提出的重调度方法显著减少了炉次加工冗余等待时间.     

Foot reach under guard rails on agricultural machinery

Foot and leg injuries of workers using agricultural field machines frequently occur when contact is made with rotating components. This paper presents the results of a study carried out to determine how far people can reach under barriers. The results show that even at a low barrier height of 200 mm above the ground some short people can get their lower leg well under the barrier and reach considerable distances. Guarding of machines to minimise leg and foot injuries is therefore likely to be a compromise between desirable standards and practical considerations.     

Bicriteria scheduling of a material handling robot in an m-machine cell to minimize the energy consumption of the robot and the cycle time

This study considers a flowshop type production system consisting of m machines. A material handling robot transports the parts between the machines and loads and unloads the machines. We consider the sequencing of the robot moves and determining the speeds of these moves simultaneously. These decisions affect both the robot’s energy consumption and the production speed of the system. In this study, these two objectives are considered simultaneously. We propose a second order cone programming formulation to find Pareto efficient solutions. We also develop a heuristic algorithm that finds a set of approximate Pareto efficient solutions. The conic formulation can find robot schedules for small cells with less number of machines in reasonable computation times. Our heuristic algorithm can generate a large set of approximate Pareto efficient solutions in a very short computational time. Proposed solution approaches help the decision-maker to achieve the best trade-off between the throughput of a cell and the energy efficiency of a material handling robot.     

Qualitative analysis of goat and sheep production data using self-organizing maps

Abstract: The aim of this study was to analyse the relationship between different small ruminant livestock production systems with different levels of specialization. The analysis is carried out by using the self-organizing map. This tool allows high-dimensional input spaces to be mapped into much lower-dimensional spaces, thus making it much more straightforward to understand any set of data. These representations enable the visual extraction of qualitative relationships among variables (visual data mining), converting the data to maps. The data used in this study were obtained from surveys completed by farmers who are principally dedicated to goat and sheep production. With the self-organizing map we found a relationship between qualitative and quantitative variables showing that more specialized farms have greater milk incomes per goat, highlighting farms that have a greater number of animals, better facilities (including milking machines) or animals fed with elaborated diets. The use of self-organizing maps for the analysis of this kind of data has proven to be highly valuable in extracting qualitative conclusions and in guiding improvements in farm performance.     

云环境下基于改进NSGA II的虚拟机调度算法

在云环境中,如何将大量的虚拟机调度到物理节点上是一个基本且复杂的问题。文中首先对虚拟机的调度建立装箱问题模型,将该模型的求解转化一个多目标优化问题,目标分别为负载均衡、提高任务执行效率和降低能耗;接着对基于非支配排序的遗传算法（ Non-dominated Sorting Genetic Algorithm,NSGA II）进行改进,利用回溯法中的剪枝函数确定最优初始种群,引入正态分布密度函数限制优秀精英。仿真结果表明,基于改进NSGA II的虚拟机调度算法在任务执行时间、负载均衡和能量消耗三个方面优于其他一些常用算法。     

Some experiments in the evaluation of a character recognition scanner

For character recognition machines in which the design of the logic is time consuming and expensive, a method for evaluating the character recognition scanner prior to designing the recognition logic is desirable. A method for evaluating a character recognition scanner by evaluating the patterns it produces is described. The method, for a given set of parameters, assigns to each pattern a figure of merit that measures the difficulty of recognizing the pattern. A number of experiments show that the evaluation method produced results comparable to results produced by a recognition logic designed by engineers. On a sample of 81,200 patterns, the evaluation method showed in this experiment that 0.20% of the patterns would be difficult to recognize, while for the same patterns, logic designed by engineers failed to recognize or misrecognized 0.24% of the patterns.     

Model reduction of finite-state machines by contraction

This paper discusses an approach to the model reduction of discrete event systems represented by finite-state machines. A set of good reduced-order approximations of a deterministic finite-state machine M can be efficiently computed by looking at its contractions, i.e., finite-state machines constructed from M by merging two states. In some particular case, it is also possible to prove that the approximations thus constructed are infimal, in the sense that there do not exist better approximations with the same number of states. This paper also defines a merit function to choose, among a set of approximations, the best one with respect to a given observed behavior     

Annual planning of harvesting resources in the forest industry

A cost‐efficient use of harvesting resources is important in the forest industry. The main planning is carried out in an annual resource plan that is continuously revised. The harvesting operations are divided into harvesting and forwarding. The harvesting operation fells trees and puts them in piles in the harvest areas. The forwarding operation collects piles and moves them to storage locations adjacent to forest roads. These operations are conducted by machines (harvesters, forwarders and harwarders), and these are operated by crews living in cities/villages that are within some maximum distance from the harvest areas. Machines, harvest teams and harvest areas have different characteristics and properties and it is difficult to find the best possible match throughout the year. The aim of the planning is to find an annual plan with the lowest possible cost. The total cost is based on three parts: production cost, traveling cost and moving cost. The production cost is the cost for the harvesting and forwarding. The traveling cost is the cost for driving back and forwards (daily) from the home base to the harvest area and the moving cost is associated with moving the machines and equipment between harvest areas. The Forest Research Institute of Sweden (Skogforsk), together with a number of Swedish forest companies, has developed a decision support platform for the planning. One important element of this platform is that it should find high‐quality plans within short computational times. One central element is an optimization model that integrates the assignment of machines to harvest areas and schedules the harvest areas during the year for each machine. The problem is complex and we propose a two‐phase solution method where, first, we solve the assignment problem and, second, the scheduling. In order to be able to control the scheduling in phase 1 as well, we have introduced an extra cost component that controls the geographical distribution of harvest areas for each machine in phase 1. We have tested the solution approach on a case study from one of the larger Swedish forest companies. This case study involves 46 machines and 968 harvest areas representing a log volume of 1.33 million cubic meters. We describe some numerical results and experience from the development and tests.     

基于无线传感网络的爆炸场振动监测系统

爆炸场振动测试中节点分布范围广、数量多,对各测试节点的状态监控及全局管理难以有效实现,传统测试方案中节点部署后难以快速更改状态;针对上述问题,依据模块化、标准化和稳定性原则,设计了一种基于无线技术的振动监测系统;给出了爆炸场振动监测系统的基本功能单元,包括数据采集设备、无线组网设备;数据采集设备具有高精度采集、数据存储、高精度同步、定位定姿等功能;利用无线网桥技术构建了覆盖广域范围的无线网络,支持IEEE802.11 n/ac协议,实现了对远程分布式测试节点的集中管理、状态监控、数据传输,也可对指定测试节点的工作模式进行快速设置,以满足测试需求;测试节点的振动测量范围为0～10 g,室外1公里数据传输;通过模拟测试试验验证了系统的有效性,各项功能满足工程需要.     

An experimental study on pedestrian classification

Detecting people in images is key for several important application domains in computer vision. This paper presents an in-depth experimental study on pedestrian classification; multiple feature-classifier combinations are examined with respect to their ROC performance and efficiency. We investigate global versus local and adaptive versus nonadaptive features, as exemplified by PCA coefficients, Haar wavelets, and local receptive fields (LRFs). In terms of classifiers, we consider the popular support vector machines (SVMs), feedforward neural networks, and k-nearest neighbor classifier. Experiments are performed on a large data set consisting of 4,000 pedestrian and more than 25,000 nonpedestrian (labeled) images captured in outdoor urban environments. Statistically meaningful results are obtained by analyzing performance variances caused by varying training and test sets. Furthermore, we investigate how classification performance and training sample size are correlated. Sample size is adjusted by increasing the number of manually labeled training data or by employing automatic bootstrapping or cascade techniques. Our experiments show that the novel combination of SVMs with LRF features performs best. A boosted cascade of Haar wavelets can, however, reach quite competitive results, at a fraction of computational cost. The data set used in this paper is made public, establishing a benchmark for this important problem     

Genetic algorithm for balancing reconfigurable machining lines

We consider the problem of designing a reconfigurable machining line. Such a line is composed of a sequence of workstations performing specific sets of operations. Each workstation is comprised of several identical CNC machines (machining centers). The line is required to satisfy the given precedence order, inclusion, exclusion and accessibility constraints on the given set of operations. Inclusion and exclusion are zoning constraints which oblige or forbid certain operations to be performed on the same workstation. The accessibility constraints imply that each operation has a set of possible part positions under which it can be performed. All the operations performed on the same workstation must have a common part position. Workstation times are computed taking into account processing and setup times for operations and must not exceed a given bound. The number of CNC machines at one workstation is limited, and the total number of machines must be minimized. A genetic algorithm is proposed. This algorithm is based on the permutation representation of solutions. A heuristic decoder is suggested to construct a solution from a permutation, so that the output solution is feasible w.r.t. precedence, accessibility, cycle time, and exclusion constraints. The other constraints are treated with a penalty approach. For a local improvement of solutions, a mixed integer programming model is suggested for an optimal design of workstations if the order of operations is fixed. An experimental evaluation of the proposed GA on large scale test instances is performed.     

发动机舱灭火剂浓度测试设备的设计

随着人民生活水平的提高,对出行的要求越来越高,飞机是出行最便捷的交通工具之一.但是发动机舱火灾引起的事故越来越多.发动机灭火系统是保证飞机安全运行的重要部分.发动机舱灭火剂浓度测试设备是验证发动机灭火系统的重要设备.因此,进行发动机舱灭火剂浓度测试设备的研究具有重要的意义.设计了一套发动机舱灭火剂浓度测试设备,基于压差检测原理的灭火剂浓度测试方法,用于测量飞机发动机舱内Halon 1301灭火剂浓度值.采用高精度测试传感器和数据采集系统,具有较高的响应速度,能够满足系统实时性高的要求.通过试验对该设备进行了验证,该测试设备达到了设计要求,对民用飞机发动机灭火系统的研制具有重要意义.该设备具有多功能、高精度、实时性、运行稳定和界面友好的特点,能够满足发动机舱灭火剂浓度测试的需求.