小流域设计洪水计算方法的探讨

利用实例对各常用设计洪水流量计算方法进行比较分析,指出各方法的特点。     

水利工程设计概算编制中的主要问题及对策

水利工程概算编制是工程设计的重要组成部分,对于合理确定工程造价预算、确保有效控制工程项目投资规模、合理使用投资、提高投资回报率,是必不可少的.本文简要归纳了一些普遍存在于水利工程设计概算编制中的问题,并结合工程实际提出了几项应对措施,以期提升设计概算编制的质量、保证项目投资控制目标的实现,从而取得较好的投资效益和社会效益.     

建设项目设计阶段投资控制系统的建立与分析

针对建设设计阶段独立使用价值工程、优化设计和限额设计等方法进行投资控制的局限性,借鉴系统论、控制论、信息论等思想和方法,建立了设计阶段投资控制系统。系统主要由探测元件、控制元件和执行元件组成,探测元件进行设计阶段的信息收集;控制元件通过审核将各项投资控制活动与投资控制目标进行对比,提出应对策略;执行元件完成应对策略。通过投资控制系统的执行,实现对设计阶段各项活动的全面系统控制,从管理层面上解决设计阶段投资控制活动割裂问题,进而改善设计阶段整体投资控制效果。     

Effect of display location on control-display stereotype strength for translational and rotational controls with linear displays

Experiments were designed to investigate the effects of control type and display location, relative to the operator, on the strength of control/display stereotypes. The Worringham and Beringer Visual Field principle and an extension of this principle for rotary controls (Hoffmann E.R., and Chan A.H.S. 2013). “The Worringham and Beringer ‘Visual Field’ Principle for Rotary Controls. Ergonomics.” 56 (10): 1620–1624) indicated that, for a number of different control types (rotary and lever) on different planes, there should be no significant effect of the display location relative to the seated operator. Past data were surveyed and stereotype strengths listed. Experiments filled gaps where data are not available. Six different control types and seven display locations were used, as in the Frame of Reference Transformation Tool (FORT) model of Wickens et al. (Wickens, C.D., Keller, J.W., and Small, R.L. (2010). “Left. No, Right! Development of the Frame of Reference Transformation Tool (FORT).” Proceedings of the Human Factors and Ergonomics Society 54th Annual Meeting September 2010, 54: 1022–1026). Control/display arrangements with high stereotype strengths were evaluated yielding data for designers of complex control/display arrangements where the control and display are in different planes and for where the operator is moving. It was found possible to predict display/control arrangements with high stereotype strength, based on past data.

Practitioner Summary: Controls and displays in complex arrangements need to have high compatibility. These experiments provide arrangements for six different controls (rotary and translational) and seven different display locations relative to the operator.     

The Relevance of Laboratory Studies to Practical Situations

By their very nature laboratory experiments are at best only rough and approximate models of any real-life situation. First of all the possible independent variables that influence behaviour in any practical situation, a laboratory experiment selects only a. few for test. As a result, hidden or unsuspected interactions in real-life may easily nullify, or even reverse, conclusions arrived at in the laboratory. Second, variables always change when they are brought into the laboratory. Third, the effect of controlling extraneous or irrelevant variables in the laboratory is to increase the precision of an experiment but at the risk of discovering effects so small that they are of no practical importance. Fourth, the dependent variables (or criteria) used in laboratory experiments are variables of convenience. Rarely are they selected for their relevance to some practical situation. Last, the methods used to present variables in the laboratory are sometimes artificial and unrealistic. The safest and most honest conclusion to draw from all these considerations is that one should generalize with extreme caution from the results of laboratory experiments to the solution of practical problems.     

Denotation and connotation in the human – computer interface: The ‘Save as …’ command

This paper presents a semiotic technique as a means of exploring meaning and understanding in interface design and use. This is examined through a study of the interaction between the ‘file’ metaphor and ‘save as’ command metaphor. The behaviour of these (from a functional or computational basis) do not exactly match, or map onto, the meaning of the metaphor. We examine both the denotation of a term to the user, i.e. its literal meaning to that person, and the term's connotations, i.e. any other meanings associated with the term. We suggest that the technique applied is useful in predicting future problems with understanding the use of metaphor at the interface and with designing appropriate signification for human-computer interaction. Variation in connotation was expected but a more fundamental difference in denotation was also uncovered. Moreover, the results clearly demonstrate that consistency in the denotation of a term is critical in achieving a good user understanding of the command.     

An ergonomic comparison of firearm safety mechanisms

As with most machines, the integral safety mechanism on firearms is vital to injury or fatality free operation. Presently, there is little or no standardisation in the design of these mechanisms. In this investigation, five existing designs found on both military and commercial rifles were evaluated ergonomically to determine the most effective characteristics for incorporation into future designs. The designs were evaluated experimentally on ease of use, visual effectiveness and operational impact. Three groups, representing a total of 30 subjects with widely varying experience, were selected. Results strongly suggest that safeties whose actuators are mounted within easy reach of the trigger finger are preferred and have the least operational impact. Subjects also preferred and were more adept at recognising safety status when the indicator was located on the receiver/barrel along the normal line of sight. Subjects more often correctly identified safety status when the indicator utilised colouring, was clearly marked and/or was in the normal line of sight. The results of this research prove that ergonomics can contribute to the understanding of firearm safety dynamics. The two essential components of safety mechanism design identified in this investigation, unambiguous status visibility and impact-free operation, are also likely to have implications in non-firearm safety mechanism design. This is particularly true for devices whose inadvertent operation can cause injury, as well as systems in which operational effectiveness can be jeopardised when attentiveness or operational control are lost in the process of actuating a poorly designed safety mechanism.     

Optimal design of butterfly-shaped linear ultrasonic motor using finite element method and response surface methodology

A new method for optimizing a butterfly-shaped linear ultrasonic motor was proposed to maximize its mechanical output. The finite element analysis technology and response surface methodology were combined together to realize the optimal design of the butterfly-shaped linear ultrasonic motor. First, the operation principle of the motor was introduced. Second, the finite element parameterized model of the stator of the motor was built using ANSYS parametric design language and some structure parameters of the stator were selected as design variables. Third, the sample points were selected in design variable space using latin hypercube Design. Through modal analysis and harmonic response analysis of the stator based on these sample points, the target responses were obtained. These sample points and response values were combined together to build a response surface model. Finally, the simplex method was used to find the optimal solution. The experimental results showed that many aspects of the design requirements of the butterfly-shaped linear ultrasonic motor have been fulfilled. The prototype motor fabricated based on the optimal design result exhibited considerably high dynamic performance, such as no-load speed of 873 mm/s, maximal thrust of 27.5 N, maximal efficiency of 43%, and thrust-weight ratio of 45.8.     

售楼管理系统的分析与设计

随着产业的不断发展,将楼盘的销售推向"无纸化"已成为当地房地产售楼管理的当务之急,本文在需求分析的基础上确定了系统的四大功能模块,即房产管理模块、客户管理模块、收费管理模块、售楼管理模块.从而满足了对售楼信息管理的需求.