语音信号端点检测的程序实现

在孤立字识别中,精确地判别语言信号的起始点和终止点是相当重要的。确定出语音信号范围的方案可以用来减少大量非实时系统的计算和提高识别精确度。本文在利用语音的某些特征参数——短时平均幅度或能量和短时平均过零率的基础上,提出了利用上述特征参数进行语音端点检测的IBM/PC机实现程序。     

Dependence of the level of residual stresses on the composition of coatings and conditions of electric arc metallization

A modified method for determining the stresses that appear in electrically metallized coatings in the process of spraying followed by cooling is suggested. Using this method, we study the dependence of internal stresses on the efficiency of the spraying process, coating thickness, and powder wire charge composition. According to the results of these investigations, all the coatings under consideration can be classified into four groups. It is shown that the residual stresses in the coatings relax as a result of plastic deformation of low-strength structural components and/or as a result of crack initiation and growth in brittle components. Depending on the correlation between the plastic and brittle phases, one observes either a single crack or numerous cracks. The strength and crack-resisting characteristics of electrically metallized coatings can be improved significantly by optimizing the powder wire charge composition.Deceased.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov. Vol. 29, No. 5, pp. 46–52, September–October, 1993.     

A methodology for economic justification of flexible manufacturing systems

This paper develops a model for the economic justification of flexible manufacturing systems. The proposed model considers the intangible and tangible benefits resulting from the implementation of advanced computer controlled manufacturing systems. The model's structure consists of a top down approach which identifies and measures the desirability of the firm's global (strategic) as well as local (tactical) objectives.     

我国企业债券风险分析

揭示了我国企业债券的违约风险问题，分析了原因，提出了化解的对策。     

Development of decision support knowledge based system for tool wear diagnosis

This paper deals with the problems faced by small and medium sized metal cutting industries, with the perspective of tool monitoring. In a small or medium size metal cutting industry employing major metal cutting process, one of the primary problem is that of tool monitoring and wear diagnosis. The problem is of immediate concern especially in those industries where the processes or operations employed are flexible and production depends entirely on orders from customers. Due to a flexible manufacturing setup, almost all major metal cutting processers need to be carried out. However, it becomes increasingly difficult for such small or medium size metal cutting industries to employ skilled manpower for each operation as well as expert technicians to supervise the operation, and carry out fault diagnosis and tool monitoring. Also, the problem associated with tool monitoring is that human operator carrying out the monitoring has to rely either on observation such as ceasing of tool, rise in temperature, generation of fumes, noisy operation, vibrations, considerable change in shape etc, or by monitoring the quality of the finished product. Also, there can be instances where the operator does notice a symptom but does not have the expertise to identify the cause of the trouble. Errors in tool monitoring can lead to considerable damage both to the machine as well as the workpiece. On the other hand, if the tool is replaced before it reaches its useful life expectancy, it leads to unnecessary additional cost. A Decision Support Knowledge Based System (DSKBS) has therefore been developed in this paper with the above considerations. The DSKBS provides the user with a friendly environment to diagnose a particular tool wear and obtain the necessary repair or replacement instructions. The goal is to increase productivity, decrease cost of operation and enhance total quality and reliability of the operation.     

Microstructural development in complex nickel-aluminum bronzes

The development of microstructure in complex nickel-aluminum bronzes of nominal composition Cu-10 wt pet Al-5 wt pct Ni-5 wt pct Fe, during continuous cooling from temperatures approaching the solidus, has been investigated using optical and electron microscopic techniques. At high temperatures the alloy consists of bccβ phase, and as the temperature is lowered the fcc copper-rich α phase is precipitated with a Widmanstätten morphology. As the temperature continues to decrease, Fe₃Al precipitates form in theβ phase and this is followed by the formation of Fe₃Al precipitates in the a phase. On further cooling theβ phase decomposes eutectoidally into ga+ NiAl; the eutectoid reaction initiates at thea/β interface and grows into theβ regions. Under normal cooling conditions the decomposition ofβ into α+ NiAl does not reach completion and the remnantβ phase transforms to martensite.     

Group technology cell formation — Some new insights

A new technique for designing manufacturing cells based on the hospitality and flexibility of jobs are used. Host cells are formed and further reduction in the number of cells are achieved using the integer programming technique. An example problem has been solved using this approach. Cost data are included in the example problem for evaluating the different designs.     

A Two-Dimensional Palletizing Procedure for Warehouse Loading Operations

A common warehouse/distribution problem is the unitization of pallet loads. A linear programming model has been developed to determine optimal stacking patterns on the basis of the dimensions of the boxes that constitute the load. The desired dimensions of the finished load may be user specified. No restriction is placed on the number of boxes of various types that may be loaded. The developed model is two-dimensional and assumes that all boxes have the same height.     

Accelerated method for hydrogen degradation of structural steel

We develop a new accelerated method for aging structural materials in gaseous hydrogen. It is based on the acceleration of diffusion processes (responsible for the structural degradation of the metal) under the influence of hydrogen and can be described as thermal cycling of materials in hydrogen. The range of thermal cycling is chosen according to the data on the operating conditions of steam pipelines of thermal power plants. The structural changes detected in the metal after laboratory aging for 40h are similar to those observed after 140,000–190,000h of operation. For the quantitative estimation of the level of degradation of the metal, we use the parameters of growth of a fatigue crack. It is experimentally shown that the effective threshold fatigue characteristics can be useful for the analysis of the current state of the metal and the proposed method of aging can be used for the determination of its residual service life. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 34, No. 4, pp. 45–52, July–August, 1998.